Electrosurgical system

ABSTRACT

Phase end point determination is provided to automatically halt the application of energy to tissue. Prior to the application of energy, the phase end point determination is identified by measuring the product of permittivity and conductivity of the tissue to be treated.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/416,128, entitled “ELECTROSURGICAL SYSTEM”, filed Mar. 31, 2009,currently pending, which claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/040,980, entitled “FEEDBACK CONTROL MECHANISMFOR FUSING BIOLOGICAL TISSUE WITH HIGH FREQUENCY ELECTRICAL ENERGY”,filed Mar. 31, 2008; U.S. Provisional Patent Application Ser. No.61/040,994, entitled “FUSING BIOLOGICAL TISSUE WITH HIGH FREQUENCYELECTRICAL ENERGY”, filed Mar. 31, 2008; U.S. Provisional PatentApplication Ser. No. 61/040,957, entitled “METHOD AND APPARATUS FORBLOODLESS TISSUE DISSECTION”, filed Mar. 31, 2008; U.S. ProvisionalPatent Application Ser. No. 61/040,828, entitled “LAPAROSCOPIC BIPOLARELECTRICAL INSTRUMENT”, filed Mar. 31, 2008; U.S. Provisional PatentApplication Ser. No. 61/040,890, entitled “APPARATUS AND METHOD FORFUSION OF LIVING TISSUE”, filed Mar. 31, 2008; U.S. Provisional PatentApplication Ser. No. 61/041,045, entitled “WELDING BIOLOGICAL TISSUEWITH HIGH FREQUENCY ELECTRICAL ENERGY”, filed Mar. 31, 2008; U.S.Provisional Patent Application Ser. No. 61/041,012, entitled “ELECTRICALCONTROL CIRCUIT FOR FUSING OF BIOLOGICAL TISSUE WITH HIGH FREQUENCYELECTRICAL ENERGY”, filed Mar. 31, 2008; U.S. Provisional PatentApplication Ser. No. 61/115,756, entitled “METHOD AND APPARATUS FORELECTROSURGICAL TISSUE DISSECTION”, filed Nov. 18, 2008. All of theseapplications are incorporated herein by reference in their entireties.

BACKGROUND

1. Field

The present application relates generally to electrosurgical systems andmethods. More specifically, the present application relates todetermination of an electrosurgery endpoint using phase shiftmonitoring.

2. Discussion of the Relevant Art

Surgical procedures often involve cutting and connecting bodily tissueincluding organic materials, musculature, connective tissue and vascularconduits. For centuries, sharpened blades and sutures have beenmainstays of cutting and reconnecting procedures. As bodily tissue,especially relatively highly vascularized tissue is cut during asurgical procedure, it tends to bleed. Thus, medical practitioners suchas surgeons have long sought surgical tools and methods that slow orreduce bleeding during surgical procedures.

More recently, electrosurgical tools have become available that useelectrical energy to perform certain surgical tasks. Typically,electrosurgical tools are hand tools such as grapsers, scissors,tweezers, blades, needles, and other hand tools that include one or moreelectrodes that are configured to be supplied with electrical energyfrom an electrosurgical generator including a power supply. Theelectrical energy can be used to coagulate, fuse, or cut tissue to whichit is applied. Advantageously, unlike typical mechanical bladeprocedures, application of electrical energy to tissue tends to stopbleeding of the tissue.

Electrosurgical tools typically fall within two classifications:monopolar and bipolar. In monopolar tools, electrical energy of acertain polarity is supplied to one or more electrodes on the tool. Aseparate return electrode is electrically coupled to a patient.Monopolar electrosurgical tools can be useful in certain procedures, butcan include a risk of certain types of patient injuries such aselectrical burns often at least partially attributable to functioning ofthe return electrode. In bipolar electrosurgical tools, one or moreelectrodes is electrically coupled to a source of electrical energy of afirst polarity and one or more other electrodes is electrically coupledto a source of electrical energy of a second polarity opposite the firstpolarity. Thus, bipolar electrosurgical tools, which operate withoutseparate return electrodes, can deliver electrical signals to a focusedtissue area with a reduced risk of patient injuries.

Even with the relatively focused surgical effects of bipolarelectrosurgical tools, however, surgical outcomes are often highlydependent on surgeon skill. For example, thermal tissue damage andnecrosis can occur in instances where electrical energy is delivered fora relatively long duration or where a relatively high-powered electricalsignal is delivered even for a short duration. The rate at which atissue will achieve the desired coagulation or cutting effect upon theapplication of electrical energy varies based on the tissue type and canalso vary based on pressure applied to the tissue by an electrosurgicaltool. However, even for a highly experienced surgeon, it can bedifficult for a surgeon to assess how quickly a mass of combined tissuetypes grasped in an electrosurgical instrument will be fused a desirableamount.

Attempts have been made to reduce the risk of tissue damage duringelectrosurgical procedures. For example, previous electrosurgicalsystems have included generators that monitor an ohmic resistance ortissue temperature during the electrosurgical procedure, and terminatedelectrical energy once a predetermined point was reached. However, thesesystems have had shortcomings in that they have not provided consistentresults at determining tissue coagulation, fusion, or cutting endpointsfor varied tissue types or combined tissue masses. These systems canalso fail to provide consistent electrosurgical results among use ofdifferent tools having different tool and electrode geometries.Typically, even where the change is a relatively minor upgrade to toolgeometry during a product's lifespan, the electrosurgical generator mustbe recalibrated for each tool type to be used, a costly, time consumingprocedure which can undesirably remove an electrosurgical generator fromservice.

SUMMARY

In view of at least the foregoing shortcomings of the previouselectrosurgical systems, there is a need in the art to improve controlof electrosurgical procedures to enhance consistency of electrosurgicalresults among electrosurgical tools and tissue types. Accordingly, thereis a need for an improved electrosurgical system that can accuratelyassess an electrical energy application endpoint for a desiredelectrosurgical procedure. There is also a need for an electrosurgicalsystem that monitors tissue properties during the electrosurgicalprocedure to assess the energy application endpoint. There is also aneed for an improved electrosurgical system that can rapidly accommodatevarious electrosurgical tools with minimal impact on surgical outcome.To address some or all of these needs and provide various additionaladvantages as discussed below in greater detail, various embodiments,methods, systems, and apparatuses for electrosurgical procedures areprovided.

In various embodiments, methods and apparatuses for bloodless dissectionof connective and vascular tissue are provided. The various methods andapparatuses described herein can be used in minimally invasive surgery,particularly laparoscopic surgery.

In certain embodiments, an electrosurgical tool comprises a handleassembly, an elongate shaft, a jaw assembly, and a force regulationmechanism. The handle assembly comprises a stationary handle and anactuation handle movably coupled to the stationary handle. The elongateshaft extends distally from the handle. The elongate shaft has aproximal end and a distal end defining a central longitudinal axistherebetween. The jaw assembly is positioned on the distal end of theelongate shaft. The jaw assembly comprises a first jaw and a second jaw.The first jaw has an inner surface, an outer surface, and at least oneelectrode disposed on the inner surface. The second jaw has an innersurface, an outer surface, and at least one electrode disposed on theinner surface. The jaw assembly is actuatable by movement of the ff froman open configuration in which the inner surface of the first jaw isspaced apart from the inner surface of the second jaw to a closedconfiguration in which the inner surface of the first jaw is proximatethe inner surface of the second jaw. The force regulation mechanismcouples the handle assembly to the jaw assembly. The force regulationassembly is configured such that in the closed configuration, the jawassembly delivers a gripping force between the first jaw and the secondjaw between a predetermined minimum force and a predetermined maximumforce.

In other embodiments, an electrosurgical tool is provided comprising ahandle assembly, an elongate shaft, and a jaw assembly. The handleassembly comprises a moveable actuation handle. The elongate shaftextends distally from the handle. The elongate shaft has a proximal endand a distal end defining a central longitudinal axis therebetween. Thejaw assembly is positioned on the distal end of the elongate shaft. Thejaw assembly comprises a first jaw, a second jaw, and a blade. The firstjaw has an inner surface, an outer surface, a proximal end and a distalend, and at least one electrode disposed on the inner surface. Thesecond jaw has an inner surface, an outer surface, a proximal end and adistal end and at least one electrode disposed on the inner surface. Theblade is advanceable along the inner surface of the first jaw along acutting path defined between a retracted position adjacent the proximalend and an advanced position between the proximal end and the distalend. The jaw assembly is actuatable from an open configuration to aclosed configuration by movement of the actuation handle. The at leastone electrode on the first jaw and the at least one electrode on thesecond jaw define a sealing area enclosing the cutting path of theblade.

In other embodiments, an electrosurgical tool is provided comprising ahandle assembly, an elongate shaft, and a jaw assembly. The elongateshaft extends distally from the handle assembly. The shaft having aproximal end and a distal end defining a central longitudinal axistherebetween. The jaw assembly is positioned on the distal end of theelongate shaft. The jaw assembly comprises a first jaw and a second jaw.The first jaw has an inner surface, an outer surface, a proximal end anda distal end, and at least one fusion electrode disposed on the innersurface. The second jaw has an inner surface, an outer surface, aproximal end and a distal end and at least one fusion electrode disposedon the inner surface and a cutting electrode disposed on the outersurface.

In certain embodiments, an electrosurgical system for performingsurgical procedures on body tissue of a patient comprises anelectrosurgical generator and an electrosurgical tool. Theelectrosurgical tool comprises a memory module storing tool data. Theelectrosurgical generator is configured to receive the tool data fromthe memory module and apply an electrosurgical signal profile to theelectrosurgical tool based on the tool data.

In other embodiments, an electrosurgical generator for performingsurgical procedures on body tissue of a patient comprises a powersupply, a signal generation module, and a first tool port. The signalgeneration module is electrically coupled to the power supply. Thesignal generation module is configured to generate a radiofrequencysignal. The first tool port is configured to interface with anelectrosurgical tool having tool data stored therein. The first toolport is adapted to receive the tool data stored on the electrosurgicaltool and to supply the radiofrequency signal from the signal generationmodule to the tool.

In some embodiments, a controller for electrosurgical tools comprises afirst actuator, a second actuator, and a tool selector. The firstactuator is movable between an on position and an off position foractuating a first electrosurgical action when in the on position. Thesecond actuator is movable between an on position and an off positionfor actuating a second electrosurgical action when in the on position.The tool selector has a first state wherein the controller is adapted tobe operatively coupled to a first electrosurgical tool and a secondstate wherein the controller is adapted to be operatively coupled to asecond electrosurgical tool.

In certain embodiments, a surgical tool can comprise jaw elements havinga plurality of electrodes to be used for both electrosurgicalcoagulation and cutting. The electrodes can be powered in a firstconfiguration to provide coagulation—leading to hemostasis of smallvascular vessels and tissue—and powered in a second configuration forelectrosurgical cutting of the coagulated tissue. The two poweredconfigurations can be generated by addressing different electrodes onthe jaw elements and applying them with voltages appropriate forelectrosurgical coagulation and/or cutting. In some embodiments, thesurgical tool can initially be powered in the first configuration toprovide coagulation, and then can be powered in the second configurationfor electrosurgical cutting. In other embodiments, the electrosurgicaltool can be powered only in a coagulating configuration to achievetissue hemostasis, only in a cutting configuration to dissect tissue, orin a cutting configuration followed by a coagulation configuration.

At the same time, various embodiments of the surgical tools describedherein can include different electrode configurations. I.e., while inone embodiment only the lower jaw is utilized to provide bothcoagulation and cutting functions, another embodiment can also employthe upper jaw element to be used in the coagulation and/or cuttingprocess. In yet another embodiment, each jaw element can carry multipleelectrode elements, greatly increasing the functionality of the tool. Aspecific electrode arrangement can allow for tools that are moresuitable for particular surgical procedures.

Another aspect of the surgical tools described herein relates toactivation and deactivation of one or multiple electrodes, based on theposition of the jaw elements. This position-based actuation allows, forexample, activation of the upper jaw electrodes only in a near-closedposition of the tool (or, in other embodiments, in an opened ornear-opened position of the tool). In some embodiments, electricalswitches in the jaw element driving mechanism can be positioned in ahand-piece of the surgical tool to selectively activate and deactivateone or multiple electrodes based on a position of the jaw elements. Inother embodiments, the activation and deactivation can be performed bysliding contacts that are assembled in the hand-piece.

Yet another aspect of the surgical tools described herein is theautomated switching from coagulation to cutting, enabled by use of amulti-electrode generator. Here, a tissue feedback mechanism triggersboth switching from one set of coagulation electrodes (applied withvoltages appropriate for coagulation) to another set of cuttingelectrodes (applied with voltages appropriate for cutting). As such,each individual tool electrode can be relayed through a bus-barconnection to any polarity of choice of the power supply. In addition,tool position switches in the hand tool can provide with logic switchingfor the population of different coagulation and/or cutting settings,depending on the specific tool position.

In certain embodiments, an electrosurgical tool is provided comprising afirst jaw, a second jaw, a first electrode, a second electrode, and athird electrode. The second jaw is pivotable with respect to the firstjaw. The first electrode is positioned on the first jaw. The secondelectrode is positioned on the first jaw. The third electrode ispositioned on the first jaw. The electrosurgical tool can be selectivelyconfigurable in a coagulation configuration such that at least one ofthe first, second, and third electrodes is electrically coupled with asource of electrical energy having a first polarity and at least oneother of the electrodes is electrically coupled with a source ofelectrical energy having a second polarity generally opposite the firstpolarity and in a cutting configuration such that one of the first,second, and third electrodes is electrically coupled with a source ofelectrical energy having a cutting voltage and at least one other of theelectrodes is configured to be a return electrode.

In other embodiments, an electrosurgical tool having a proximal end anda distal end is provided comprising a distal end-piece, an elongateshaft, a handle assembly, and a switching mechanism. The distalend-piece is positioned at the distal end of the tool. The distalend-piece comprises a first jaw element, a second jaw element, and aplurality of electrodes. The first and second jaw elements are movablerelative to one another between an open position and a closed position.The plurality of electrodes is disposed on at least one of the first jawelement and the second jaw element. The plurality of electrodes isselectively configurable in one of a coagulation configuration and acutting configuration. The elongate shaft has a distal end connected tothe distal end-piece and a proximal end. The handle assembly ispositioned at the proximal end of the tool and connected to the proximalend of the elongate shaft. The handle assembly comprises a hand-pieceand a trigger. The trigger is pivotally coupled to the hand-piece andoperably coupled to the distal end-piece such that movement of thetrigger relative to the hand-piece moves the first and second jawelements relative to one another. The switching mechanism iselectrically coupled to the distal end-piece to selectively configurethe plurality of electrodes in one of the coagulation configuration andthe cutting configuration.

In other embodiments, a method for substantially bloodless dissection ofbiological tissue is provided. The method comprises positioning anelectrosurgical tool adjacent tissue to be dissected, measuring tissueproperties to determine the switching point from coagulation to cutting,applying electrical energy to the electrosurgical tool, assessing thetissue coagulation (phase shift) through a feedback loop, switching aconfiguration of the electrosurgical tool, and applying electricalenergy to the electrosurgical tool in a cutting configuration. Theelectrosurgical tool comprises a plurality of electrodes configurable inone of a coagulation configuration and a cutting configuration. Applyingelectrical energy to the electrosurgical tool comprises applyingelectrical energy to the electrosurgical tool in the coagulationconfiguration to achieve hemostasis in the tissue. Switching theelectrosurgical tool comprises switching the electrosurgical tool to thecutting configuration.

In some embodiments, a method for controlling an output of anelectrosurgical generator operatively coupled to a bipolarelectrosurgical device is provided. The method comprises measuring aphase angle, determining a target phase angle, measuring the phase angleof a second measurement signal, and ceasing delivery of a treatmentsignal. Measuring the phase angle comprises measuring a phase angle of afirst measurement signal applied to tissue of a patient via at least oneelectrode of the electrosurgical device. The first measurement signal isapplied to the tissue prior to treatment of the tissue by theelectrosurgical device. Determining a target phase angle comprisesdetermining a target phase angle using the phase angle of the firstmeasurement signal. Following delivery of a treatment signal comprisesfollowing delivery of a treatment signal to the tissue. Measuring thephase angle of a second measurement signal comprises measuring the phaseangle of a second measurement signal applied to the tissue. Thetreatment signal is capable of causing modification of the tissue.Ceasing delivery of the treatment signal comprises ceasing delivery ofthe treatment signal to the tissue when the phase angle of the secondmeasurement signal reaches the target phase angle.

In other embodiments, a method for controlling an output of anelectrosurgical generator operatively coupled to a bipolarelectrosurgical device is provided. The method comprises determiningpermittivity and conductivity of tissue, determining a threshold phaseangle, measuring a phase angle, and ceasing the delivery of thetreatment signal. Determining permittivity and conductivity of tissuecomprises determining permittivity and conductivity of tissue of apatient using a measurement signal. The measurement signal is applied totissue of a patient via at least one electrode of the electrosurgicaldevice. The measurement signal is applied to the tissue prior tomodification of the tissue by the electrosurgical device. Determining athreshold phase angle comprises determining a threshold phase anglebased on the permittivity and the conductivity of the tissue. Measuringa phase angle comprises measuring a phase angle of a signal applied tothe tissue. Ceasing the delivery of the treatment signal comprisesceasing the delivery of the treatment signal to the tissue when thephase angle of the signal reaches the threshold phase angle.

In other embodiments, a method of characterizing tissue prior to thedelivery of electrosurgical energy to the tissue via a bipolarelectrosurgical device is provided. The method comprises measuring phaseangle, determining the product of the relative permittivity andconductivity, and characterizing the tissue. Measuring phase anglecomprises measuring phase angle of a measurement signal applied totissue of a patient via at least one electrode of the electrosurgicaldevice. The measurement signal is applied to the tissue at apredetermined frequency prior to modification of the tissue by theelectrosurgical device. Determining the product of the relativepermittivity and conductivity comprises determining the product of therelative permittivity and conductivity of the tissue using the phaseangle measurement and the predetermined frequency. Characterizing thetissue comprises characterizing the tissue based on the product of therelative permittivity and conductivity of the tissue.

In other embodiments, a method of characterizing tissue prior to thedelivery of electrosurgical energy to the tissue via a bipolarelectrosurgical device is provided. The method comprises generating ameasurement signal, determining a treatment endpoint condition, andstopping delivery of a treatment signal. Generating a measurement signalcomprises generating a measurement signal applied to tissue of a patientpositioned between at least two jaw members of an electrosurgicaldevice. At least one of the jaw members comprises an electrode. Themeasurement signal is delivered to the tissue via the electrode andapplied to modification of the tissue by the electrosurgical device.Determining a treatment endpoint condition comprises determining atreatment endpoint condition using the measurement signal. The treatmentendpoint condition is determined substantially independently of thedimensions of the tissue positioned between the at least two jawmembers. Stopping delivery of a treatment signal comprises stoppingdelivery of a treatment signal to the tissue when the treatment endpointcondition is reached. The treatment signal is capable of causingmodification of the tissue.

In other embodiments, an electrosurgical system for application oftreatment energy to a patient involved in bipolar electrosurgery isprovided. The system comprises an electrosurgical generator, anelectrosurgical control unit, and an electrosurgical tool. Theelectrosurgical generator is configured to generate and output atreatment energy along with a measurement signal. The electrosurgicalcontrol unit is configured to direct the output of treatment energy anda measurement signal. The electrosurgical tool is removably connected toone of the electrosurgical generator and the electrosurgical controlunit and arranged to contact tissue and apply the treatment energy andthe measurement signal to the tissue. The electrosurgical control unitmeasures permittivity and conductivity of the tissue through theapplication of the measurement signal.

BRIEF DESCRIPTION OF THE DRAWINGS

The present inventions may be understood by reference to the followingdescription, taken in connection with the accompanying drawings in whichthe reference numerals designate like parts throughout the figuresthereof.

FIG. 1A is a schematic block diagram of an embodiment of electrosurgicalsystem.

FIG. 1B is a schematic block diagram of another embodiment ofelectrosurgical system.

FIG. 2A is a perspective view of components of one embodiment of anelectrosurgical system.

FIG. 2B is a perspective view of components of one embodiment of anelectrosurgical system.

FIG. 2C is a perspective view of components of one embodiment ofelectrosurgical system.

FIG. 3A is a perspective view of an electrosurgical unit for use in anelectrosurgical system.

FIG. 3B is a front view of the electrosurgical unit of FIG. 3A.

FIG. 3C is a rearview of the electrosurgical unit of FIG. 3A.

FIG. 4A is an exemplary screenshot of a display of the electrosurgicalunit of FIG. 3A.

FIG. 4B is another exemplary screenshot of the display of theelectrosurgical unit of FIG. 3A.

FIG. 5 is a block diagram of various embodiments of an electrosurgicalunit.

FIG. 6 is a front view of a user interface of an electrosurgical unit.

FIG. 7 is a front view of a user interface of an electrosurgical unit.

FIG. 8 is a front view of a user interface of an electrosurgical unit.

FIG. 9 is a block diagram of an electrosurgical unit.

FIG. 10 is a block diagram of an electrosurgical unit.

FIG. 11 is a graphical representation of a high voltage driving signalat low frequency relative to a low voltage measurement voltage at a highfrequency.

FIG. 12 is a graphical representation of filtered measurement andcurrent signals for a time near the end of the fusion process.

FIG. 13 is a block diagram of an electrosurgical unit.

FIG. 14 is a block diagram of an electrosurgical unit.

FIG. 15 is a schematic diagram of an external measurement circuitry ofan electrosurgical unit.

FIG. 16 is a schematic diagram of switch circuitry of an electrosurgicalunit.

FIG. 17 is a schematic diagram of a phase comparator or detectioncircuitry of an electrosurgical unit.

FIG. 18 is a schematic diagram of a battery power circuitry of anelectrosurgical unit.

FIG. 19 is a schematic diagram of an input interface of anelectrosurgical unit.

FIG. 20 is a graphical representation of experimental data for thevoltage applied to the tissue during a typical a vessel fusion process.

FIG. 21 is a graphical representation of experimental data for thevoltage applied to the tissue during the measurement cycle.

FIG. 22 is a graphical representation of experimental data for thevoltage applied to the tissue during the RF measurement cycle todetermine the phase shift through the tissue.

FIG. 23 is a graphical representation of a sample of experimental datafor a typical vessel sealing process, showing a temporal showing atemporal snapshot of applied voltage, electrical current, and dissipatedpower at 1 second into the fusion.

FIG. 24 is a graphical representation of a sample of experimental datafor a typical vessel sealing process, showing the peak voltage and peakelectrical current as function of fusion time.

FIG. 25 is a graphical representation of a sample of experimental datafor a typical vessel sealing process, showing the vessel impedance asfunction of fusion time.

FIG. 26 is a graphical representation of a vessel sealing and tissuewelding process in accordance with various embodiments of the presentinvention showing the relative impedances of various tissues as afunction of time.

FIG. 27 is a graphical representation of a fusion/vessel sealing processin accordance with various embodiments of the present invention showinga temporal snapshot of applied voltage, electrical current, anddissipated power at 4 seconds into the fusion process.

FIG. 28 is a graphical representation for a fusion/vessel sealingprocess showing a temporal snapshot of applied voltage, electricalcurrent, and dissipated power at 7 seconds into the fusion process.

FIG. 29 is a graphical representation of bursting pressure as a functionof phase shift used in end point determination.

FIG. 30 is a table of dielectric constants or permittivity andconductivities for various types of biological tissue, arranged byincreasing values of the product of dielectric constants and tissueconductivity.

FIG. 31 is a graphical representation of empirically determined phaseshifts to adequately fuse and/or weld various types of biologicaltissue.

FIG. 32 is a graphical representation of endpoint phase shifts relativeto initial phase shift measurements of various types of biologicaltissue.

FIG. 33 is a graphical representation of a phase diagram of twoelectrosurgical tools and their associated capacitance and resistance.

FIG. 34 is a graphical representation of a phase diagram of anelectrosurgical tool in tissue contact and the associated capacitanceand resistance.

FIG. 35 is a graphical representation of the ohmic resistance of aporcine renal artery during the electrosurgical fusion process.

FIG. 36 is a graphical representation of phase shift during theelectrosurgical fusion process.

FIG. 37 is a graphical representation of the derivate of the phase shiftduring the electrosurgical fusion process.

FIG. 38 is a graphical representation of phase shift during theelectrosurgical fusion process.

FIG. 39 is a graphical representation of the derivate of the phase shiftduring the electrosurgical fusion process.

FIG. 40 is a block diagram of a fusion or welding process of anelectrosurgical unit.

FIG. 41A is a perspective view of an embodiment of laparoscopicsealer/divider.

FIG. 41B is a disassembled view of a laparoscopic sealer/divider of FIG.1A.

FIGS. 42A-42C are views of an actuator of the laparoscopicsealer/divider of FIG. 41A.

FIG. 43 is a top cross-sectional view of an actuator of a laparoscopicsealer/divider of FIG. 41A.

FIGS. 44A-44D are views of a shaft assembly of a laparoscopicsealer/divider of FIG. 41A.

FIGS. 45A-45C are views of a jaw assembly of a laparoscopicsealer/divider of FIG. 41A.

FIGS. 46A-46G are cross-sectional side views of a laparoscopicsealer/divider of FIG. 41A.

FIG. 47 is a perspective view of a controller of a laparoscopicsealer/divider of FIG. 41A.

FIG. 48A is a side view of a jaw assembly of a laparoscopicsealer/divider of FIG. 41A.

FIGS. 48B-48C are graphical representations of exemplary vessel sealingpressures provided by a laparoscopic sealer/divider of FIG. 41A.

FIG. 49 is a top level view of an electrode configuration of alaparoscopic sealer/divider of FIG. 41A.

FIG. 50 is a top level view of a jaw assembly of a laparoscopicsealer/divider of FIG. 41A.

FIG. 51 is a side view of a jaw assembly of a laparoscopicsealer/divider of FIG. 41A.

FIG. 52 provides views of a jaw assembly of a laparoscopicsealer/divider of FIG. 41A.

FIG. 53A is a perspective view of a jaw assembly of a laparoscopicsealer/divider of FIG. 51A.

FIG. 53B is a perspective view of an actuator of a laparoscopicsealer/divider of FIG. 41A.

FIG. 54 provides views of portions of a shaft assembly of a laparoscopicsealer/divider of FIG. 41A.

FIG. 55 provides views of a jaw assembly of a laparoscopicsealer/divider of FIG. 41A.

FIG. 56 is a perspective view of an embodiment of surgical tool for usein a laparoscopic surgical procedure.

FIG. 57 is a perspective drawing of the distal end of an exemplarytissue fusion/cutting devices.

FIGS. 58A-D are schematic drawings of various embodiments of distal endconfigurations for an electrosurgical bloodless tissue dissectiondevice.

FIGS. 59A-C are schematic drawings of active electrode switchingcircuitries in the hand tools.

FIG. 60 is a schematic drawing of the inside of the hand-piece,illustrating the embodiment of active electrode switching mechanismbased on the opening of the jaw elements.

FIG. 61 depicts another embodiment of an active electrode switchingmechanism, also based on the opening of the jaw elements.

FIG. 62 depicts an embodiment of a passive switching mechanism, alsobased on the opening of the jaw elements.

FIG. 63 depicts another embodiment of a passive switching mechanism,based on both the opening and closing of the jaw elements.

FIG. 64 depicts a schematic circuitry that connects five electrodesthrough relays to a bus bar which is relayed to a measurement circuit,or an electrosurgical power plant.

FIG. 65 schematically illustrates one embodiment of a method forsubstantially bloodless dissection of biological tissue.

FIG. 66 is a perspective view of an electrosurgical instrument in aclosed condition.

FIG. 67 is a perspective view of an electrosurgical instrument in anopen condition.

FIG. 68 is a side view of an electrosurgical instrument in an opencondition.

FIG. 69 is an enlarged perspective view of a clamping portion of anelectrosurgical instrument in an open condition.

FIG. 70 is a side section view of an electrosurgical instrument in anopen condition.

FIG. 71 is an enlarged perspective view of a clamping jaw portion withthe top clamping jaw removed.

FIG. 72 is an enlarged perspective view of an actuator for advancingelectrodes.

FIG. 73 is an enlarged side view of clamping jaws in an open conditionwith electrodes extended.

FIG. 74 is an enlarged side section view of clamping jaws in an opencondition and having electrodes extended.

FIG. 75 is an enlarged perspective view of an actuator sled andassociated electrical contacts.

FIG. 76 is an enlarged perspective view of an electrode.

FIG. 77 illustrates a relationship between clamping jaws and tissue tobe fused in a first, grasping condition.

FIG. 78 illustrates a relationship between clamping jaws and tissue tobe fused in a second, compressing condition.

FIG. 79 illustrates a relationship between clamping jaws and tissue tobe fused in a third, electrode-extending condition.

FIG. 80 illustrates a relationship between clamping jaws and tissue tobe fused in a final, electrode-extending condition.

FIG. 81 is a perspective cut-out view of a body conduit showing anelectrosurgical instrument moving into position to occlude a lumen of aconduit.

FIG. 82 is a perspective view of a body conduit showing anelectrosurgical instrument in position to occlude a lumen of a conduit.

FIG. 83 is a perspective view of a body conduit showing anelectrosurgical instrument occluding a lumen of a conduit.

FIG. 84 is a schematic diagram illustrating current concentrationthrough tissue in a first, non-contact condition.

FIG. 85 is a schematic diagram illustrating current concentrationthrough tissue in a full-contact condition.

FIG. 86 illustrates electrosurgical energy radiation associated withpenetrating electrodes.

FIG. 87 illustrates a thermal zone associated with penetratingelectrodes.

FIG. 88 illustrates a thermal zone associated with penetratingelectrodes with the electrodes withdrawn.

FIG. 89 illustrates electrosurgical energy radiation associated withpenetrating electrodes within approximated tissue.

FIG. 90 illustrates a thermal zone associated with penetratingelectrodes within approximated tissue.

FIG. 91 illustrates a thermal zone associated with penetratingelectrodes with electrodes withdrawn.

FIG. 92 is an end view of a conduit closed or occluded using a suturingtechnique.

FIG. 93 is an end view of a conduit closed or occluded using a staplingtechnique.

FIG. 94 is an end view of a conduit closed or occluded using acompressive fusion technique.

FIG. 95 is an end view of a conduit closed or occluded using acompressive fusion technique with inserted electrodes.

FIG. 96 is a graphical representation of exemplary burst pressure dataof an occlusion using a compressive fusion technique with insertedelectrodes

FIG. 97 is an enlarged perspective view of a clamping jaw showing anassociated cutting element.

FIG. 98 is an enlarged perspective view of a clamping jaw showing anassociated cutting element comprising an electrosurgical wire electrode.

FIG. 99 is an enlarged perspective view of a clamping jaw showing anassociated cutting element comprising an electrosurgical or mechanicalwedge electrode-knife.

FIG. 100 is an enlarged perspective view of a clamping jaw showing anassociated cutting element comprising an electrosurgical or mechanicaldouble edge knife.

FIG. 101 is an enlarged perspective view of a clamping jaw showing aplurality of current intensifying elements comprising holes.

FIG. 102 is an enlarged perspective view of a clamping jaw showing aplurality of current intensifying elements comprising extended posts.

FIG. 103 a is an enlarged perspective view of a clamping jaw showing aplurality of current intensifying elements comprising extended arcs.

FIG. 103 b is an enlarged perspective view of a clamping jaw showing aplurality of current intensifying elements comprising extended squares.

FIG. 103 c is an enlarged perspective view of a clamping jaw showing aplurality of current intensifying elements comprising extended rods.

FIG. 103 d is an enlarged perspective view of a clamping jaw showing aplurality of current intensifying elements comprising extended“ball-and-cups”.

FIG. 104 is an enlarged perspective view of a clamping jaw showing aplurality of current intensifying elements comprising extendedrectangles.

FIG. 105 a is an enlarged perspective view of a clamping jaw showing aplurality of current intensifying elements comprising extended ridges.

FIG. 105 b is an enlarged perspective view of a clamping jaw showing aplurality of current intensifying elements comprising linear“spicket-and-sockets”.

FIG. 106 is an enlarged perspective view of a clamping jaw showing aplurality of current intensifying elements comprising extended pyramidsor cones.

FIG. 107 shows a cross-section view of a clamping jaw with an exemplarycompressed artery with an application of electrical or thermal energy.

FIGS. 108 a and b are views of an exemplary portion of an artery sealedand cut (108 a top plan view, 108 b along 8-8).

FIGS. 109 a and b are views of an exemplary portion of tissue sealed andcut (109 a top plan view, 109 b along 9-9).

FIG. 110 shows a cross-sectional view of a clamping jaw with anexemplary compressed artery with an application of ultrasonic energy.

FIG. 111 shows a cross-sectional view of a clamping jaw with anexemplary compressed artery with an application of UV or IR radiantenergy.

DETAILED DESCRIPTION

The following description is provided to enable any person skilled inthe art to make and use the surgical tools and perform the methodsdescribed herein and sets forth the best modes contemplated by theinventors of carrying out their inventions. Various modifications,however, will remain apparent to those skilled in the art. It iscontemplated that these modifications are within the scope of thepresent disclosure.

Electrosurgical System

FIG. 1A illustrates a schematic diagram of an electrosurgical system 2.The electrosurgical system 2 can comprise an electrosurgical unit (ESU)10 and an electrosurgical tool 40. The electrosurgical tool 40 can beelectrically coupled to the electrosurgical unit 10. In someembodiments, an electronic coupler 30 such as an electrical wire, wirebundle, or cable can electrically couple the electrosurgical tool 40 tothe ESU 10. In some embodiments, the electrosurgical system 2 canoptionally further comprise an external tool controller 80.

With continued reference to FIG. 1A, the electrosurgical unit 10 cancomprise a generator 12 and a feedback circuit 20. The generator 12 caninclude an actuator 16 such as a power supply and a signal processorconfigured to generate a radiofrequency (RF) electrosurgical signal. Thegenerator 12 can further comprise a display 14. The display 14 can beconfigured to indicate the status of the electrosurgical system 2,including, among other information, the status of the actuator 16 andthe status of the electrosurgical tool 40 electrically coupled to theelectrosurgical unit 10.

With continued reference to FIG. 1A, the feedback circuit 20 of the ESU10 can comprise a phase discriminator 22, a tissue identifier 24, and anencryption module 26. In some embodiments, the phase discriminator 22can be electrically coupled to the tissue identifier 24. The phasediscriminator 22 can be configured to receive information from theelectrosurgical tool 40 electrically coupled to the ESU 10. In someembodiments, the information from the electrosurgical tool 40 comprisesinformation regarding an applied voltage and a supplied current to theelectrosurgical tool, and the phase discriminator 22 can be configuredto calculate a phase difference between the applied voltage and thesupplied current. The encryption module 26 can be configured to transmitand receive data formatted in an encrypted protocol. The encryptedprotocol can be one of several commercially-available encryptionprotocols, or, in some embodiments can be a purpose developed encryptionprotocol.

With continued reference to FIG. 1A, In some embodiments, the feedbackcircuit 20 can be one or more integrated circuits, printed circuitboards, or other processor collocated with the generator 12 within anintegrated ESU 10. As Illustrated in FIG. 1B, In other embodiments, thefeedback circuit 20′ can be electrically coupled to a stand-alonegenerator 12′ to form an ESU 10′. The tool 40 can be electricallycoupled to the feedback circuit 20′. Other aspects of electrosurgicalsystems having a stand-alone generator 12′ and feedback circuit 20′ canbe substantially similar to systems having an integrated ESU discussedwith respect to FIG. 1A.

With continued reference to FIG. 1A, the tool 40 can comprise anindicator 42, a tissue selector 50, an actuator 60, and a memory 70. Insome embodiments, the indicator 40 can comprise an audio indicator 44such as a speaker, a chime, a clicker device, or another audiogeneration device. In some embodiments, the indicator 40 can comprise avisual indicator 46 such as a lamp, an LED, a display, a counter, oranother visual indication device. In some embodiments, the visualindicator 46 comprises a multi-color LED. In some embodiments, the tool40 comprises both an audio indicator 44 and a visual indicator 46.

The tissue selector 50 can comprise an electrode assembly 52 and acutting tool 54. In various embodiments, various electrode assembliescan be configured to perform a desired electrosurgical procedure suchas, for example, coagulation, cutting, or fusion, on a particulartissue. In some embodiments, the electrode assembly 52 can be configuredfor use as a vascular sealer. In other embodiments, the electrodeassembly 52 can be configured for use as a bariatric stapler. In stillother embodiments, the electrode assembly 52 can be configured for useas a tissue cutting device. In some embodiments, the cutting tool 54 canbe a mechanical element such as a stationary or moveable blade orsharpened edge. In other embodiments, the cutting tool 54 can be anelectrosurgical element such as an energizable wire or filament.

With continued reference to FIG. 1A, the actuator 60 can be operativelycoupled to the tissue selector 50 to selectively select tissue. Forexample, in some embodiments, the tissue selector 50 can include ajaw-based grasper, and the actuator can comprise an actuation mechanismto selectively move the grasper from an open position to a closedposition. In other embodiments, it is contemplated that other tissueselectors can be used in the electrosurgical system 2. In someembodiments, the actuator 60 can also be configured to selectivelyenergize the electrodes. For example, the actuator 60 can comprise aswitch or button on the tool.

With continued reference to FIG. 1A, the tool 40 can further comprise amemory 70. In some embodiments, the memory 70 comprises an encryptionmodule 72 and a configuration device module 74. The encryption module 72can be configured to facilitate an encrypted information exchange withthe encryption module 26 on ESU 10. The configuration device module 74can store operational parameter information about the tool 40. Forexample, in some embodiments, the configuration device module 74 canstore information regarding the electrode assembly, the number of usesand total operational time of use of the tool, and other operationalparameters.

With continued reference to FIG. 1A, the electrosurgical system 2 canfurther comprise an external tool controller 80 electrically couplingthe ESU 10 to the tool 40. In some embodiments, the external toolcontroller 80 comprises a tool selector 82 such as a switch. Theexternal tool controller 80 can allow for multiple devices to connectthereto. A tool selector 82 allows selection of one of the multipledevices to be energized. For example the tool selector 82 can comprise adial, switch, or toggle. The tool actuator 84 can selectivelyelectrically couple the selected tool 40 with the ESU 10. 3

With reference to FIG. 2A, an exemplary embodiment of electrosurgicalsystem 102 is illustrated including an ESU 110, and an electrosurgicalfusion tool 120. The electrosurgical fusion tool 120 can be electricallycoupled to the ESU 110 by an electrical coupler 130 such as with ancabled connection to a tool port 112 on the ESU 110. In the illustratedembodiment, the electrosurgical fusion tool 120 comprises a tissuesealer and divider, as discussed in further detail below with respect toFIGS. 41A-55. The electrosurgical fusion tool 120 comprises visualindicators 122 such as multi-color LEDs positioned there on to apprise auser of the status of the tool. In other embodiments, theelectrosurgical fusion tool 120 can be electrically coupled to agenerator or a different electrosurgical unit. In some embodiments, amanual controller such as a hand of foot switch can be electricallycoupled to the ESU 110 or the electrosurgical fusion tool 122 to allowselective control of the tool.

With reference to FIG. 2B, an exemplary embodiment of electrosurgicalsystem 202 is illustrated including an ESU 210, and an electrosurgicaltool 220. The electrosurgical tool 220 can be electrically coupled tothe ESU 210 such as with a cabled connection to a tool port 212 on theESU 210. In the illustrated embodiment, the electrosurgical tool 220comprises an electric cutting and coagulation tool, as discussed infurther detail below with respect to FIGS. 56-65. The electrosurgicaltool 220 comprises visual indicators 222 such as multi-color LEDspositioned there on to apprise a user of the status of the tool. Inother embodiments, the electrosurgical tool 220 can be electricallycoupled to a generator or a different electrosurgical unit. In someembodiments, a manual controller such as a hand of foot switch can beelectrically coupled to the ESU 210 or the electrosurgical fusion tool222 to allow selective control of the tool.

With reference to FIG. 2C, an exemplary embodiment of electrosurgicalsystem 2302 is illustrated including an ESU 310, and an electrosurgicaltool 320. The electrosurgical tool 320 can be electrically coupled tothe ESU 310 such as with a cabled connection to a tool port 312 on theESU 310. In the illustrated embodiment, the electrosurgical tool 320comprises an electrosurgical stapling tool, as discussed in furtherdetail below with respect to FIGS. 66-111. The electrosurgical tool 320comprises visual indicators 322 such as multi-color LEDs positionedthereon to apprise a user of the status of the tool. In otherembodiments, the electrosurgical tool 320 can be electrically coupled toa generator or a different electrosurgical unit. In some embodiments, amanual controller such as a hand of foot switch can be electricallycoupled to the ESU 310 or the electrosurgical tool 322 to allowselective control of the tool.

Integrated Electrosurgical Unit

With reference to FIGS. 3A-3C, of electrosurgical unit 410 isillustrated in perspective, front, and rear views. The electrosurgicalunit 410 can be an integrated ESU as discussed above with respect toFIG. 1A, and can comprise a generator and a feedback circuit. In someembodiments, the housing or console of the electrosurgical unit 410 canbe sized and configured to fit on a standard operating room cart orstorage rack. In some embodiments, the housing or console of theelectrosurgical unit 410 can be configured to be stackable with othersurgical electrical equipment.

With reference to FIGS. 3A-3B, a perspective view of the electrosurgicalunit 410 is illustrated. In the illustrated embodiment, theelectrosurgical unit 410 comprises two dedicated tool ports 412, onebipolar tool port 414, and one electrical power port 416. In otherembodiments, electrosurgical units can comprise different numbers ofports. For example, in some embodiments, an electrosurgical unit cancomprise more or fewer than two dedicated teleports 412, more or fewerthan one bipolar tool port 414, and more or fewer than one power port416.

With continued reference to FIGS. 3A-3B, each dedicated tool port 412 isconfigured to be coupled to electrosurgical tool having a memory, asdescribed above with respect to FIG. 1A. Thus the dedicated tool ports412 can be electrically coupled to the feedback circuit of theelectrosurgical unit 410 as well as the generator. In some embodiments,the dedicated tool ports 412 con comprise multi-pin connectorscomprising a plurality of electrical connection pins or pin receptacles.In some embodiments, the connectors can comprise more than 10, forexample 20 pins or pin receptacles. As discussed above with respect toFIG. 1A, and discussed in further detail below, the dedicated tool ports412 can be configured for encrypted transmission and reception of datafrom an electrically coupled electrosurgical tool.

With continued reference to FIGS. 3A-3B, the bipolar tool port 414 caninclude a plug configured to receive a conventional bipolarelectrosurgical tool. The bipolar tool port 414 can be coupled to thegenerator of the electrosurgical unit 410. In some embodiments, thebipolar tool port 414 is not coupled to the feedback circuit of theelectrosurgical unit 410. Thus, advantageously, the electrosurgical unit410 can energize both specialized electrosurgical tools, as described infurther detail here and, conventional bipolar electrosurgical tools.Accordingly, the electrosurgical unit 410 can be used in place of astandalone bipolar electrosurgical generator without requiringadditional rack or cart space in a surgical workspace.

With continued reference to FIGS. 3A-3B, the electrical power port 416can be coupled to the generator of the electrosurgical unit 410. Theelectrical power port 416 can be configured to supply direct current.For example, in some embodiments, the electoral power port 416 canprovide approximately 12 Volts DC. The electrical power port 416 can beconfigured to power a surgical accessory, such as a respirator, pump,light, or another surgical accessory. Thus, advantageously, in additionto replacing electrosurgical generator for standard bipolar tools, theelectrosurgical unit 410 can also replace a surgical accessory powersupply. In some embodiments, replacing presently-existing generators andpower supplies with the electrosurgical unit 410 can reduce the amountof storage space required on storage racks cards or shelves in thenumber of mains power cords required in a surgical workspace.

With continued reference to FIGS. 3A-3B, the electrosurgical unit 410can comprise a display 420. In some embodiments, the display cancomprise a multi-line display capable of presenting text and graphicalinformation such as for example an LCD panel display, which, in someembodiments can be illuminated via backlight or sidelight. In someembodiments, the display 420 can comprise a multi-color display that canbe configured to display information about a particular toolelectrically coupled to the electrosurgical unit 410 and a color thatcorresponds to a standard color associated with a surgical procedure(such as, for example cutting operations displayed in yellow text andgraphics, fusion or welding operations displayed in purple, andcoagulation displayed in blue, bloodless dissection operations can bedisplayed in yellow and blue). In some embodiments, as discussed infurther detail below, the display can be configured to simultaneouslyindicate status data for a plurality of tools electrically coupled tothe electrosurgical unit 410. In some embodiments, a user can toggle thedisplay 420 between presenting status of multiple electrically connectedtools and status of a single electrically connected tool. Furtherexemplary aspects of the display are discussed generally with respect toFIGS. 4A and 4B, and more specifically with respect to operation of thesystem below.

With continued reference to FIGS. 3A-3B, the electrosurgical unit cancomprise a user interface such as, for example a plurality of buttons422. The buttons 422 can allow user interaction with the electrosurgicalunit such as, for example, requesting an increase or decrease in theelectrical energy supplied to one or more tools coupled to theelectrosurgical unit 410. In other embodiments, the display 420 can be atouch screen display thus integrating data display and user interfacefunctionalities. In some embodiments, the electrosurgical unit 410 cancomprise an audible indicator, such as a speaker or chime to alert auser of a possible error, the termination of electrical energy supplied,or other conditions. In some embodiments, the electrosurgical unit 410can be configured such that the audible indicator can sound a particularsound during cutting operations, a different sound during fusion orwelding operations, and another distinct sound during coagulationoperations to provide audible feedback to a user.

With reference to FIG. 3C, a rearview of the electrosurgical unit 410 isillustrated. In the illustrated embodiment, the rear of theelectrosurgical unit 410 includes a rear panel 430. The rear panel 430can include various ports, such as a controller port 432 configured tobe electrically coupled to an external controller such as a foot pedalcontroller, as described above with respect to FIG. 1A. The rear panel430 can also include a grounding lug. In other embodiments, one or morecontroller ports and/or the grounding lug can be located on another faceof the electrosurgical unit 410, for example on the front face or a sideface. The rear face of the electrosurgical unit 410 can include a powermodule 440 including a mains power port configured to be plugged into anAC power mains such as a wall socket and a master power switch forpowering the electrosurgical unit 410 on and off. In other embodiments,the master power switch can be positioned on another face of theelectrosurgical unit 410, for example on the front face or a side face.The rear phase of the electrosurgical unit 410 can also include a heatexchange feature, such as, for example slots, a grill, or a plurality oflouvers 450. In other embodiments, the heat exchange feature can bepositioned on another face of the electrosurgical unit 410, for exampleon the front face or a side face. The heat exchange feature can enhanceair or other fluid cooling of the generator, the feedback circuit, andother electrical components housed within the electrosurgical unit 410console.

With reference to FIG. 4A, an exemplary screen shot of the display isillustrated. In the illustrated embodiment, the display 420 can beportioned to display status information for ADC tools 460, a bipolartool 470, a first radiofrequency electrosurgical tool 480, and a secondradiofrequency electrosurgical tool 490, corresponding to the four portson the front panel of the electrosurgical unit 410 discussed above withrespect to FIGS. 3A, 3B in the illustrated screenshot, a first section462 displays information regarding the DC tool 460. A second section 472displays information regarding the bipolar electrosurgical tool 470. Avisual indicator such as a status bar graph 474 can be used toillustrate a proportion of total available electrical energy to beapplied to the bipolar electrosurgical tool 470 when actuated. Asdiscussed above, the visual indicator can be color-coded to indicate asurgical procedure to be performed. A third section 482 can displayinformation regarding a first radiofrequency electrosurgical tool 480with a visible indicator such as a status bar graph 484. A fourthsection 492 can display information regarding a second radiofrequencyelectrosurgical tool 490 with separate visual indicators or bar graphs494, 496, 498 for each type of surgical operation that can be performedfor that tool. For example an electrosurgical tool operable to cut,coagulate, or fuse tissue could have three color-coded bar graphs. Thedisplay 420 can also include a controller icon, such as a foot pedalicon 476 positions in a section corresponding to a tool to which a footpedal is electrically coupled.

With reference to FIG. 4B, another exemplary screen shot of the display420 is illustrated. It is illustrated, the display has been configuredto maximize information presentation of the section 492 corresponding tothe second of electrosurgical tool. As discussed above, in someembodiments electrosurgical unit can be configurable display statusinformation regarding a single tool electrically coupled thereto. Insome embodiments, the electrosurgical unit can allow user manipulationof energy levels applied to electrosurgical tool. In one configuration,energy levels for an electrosurgical tool can be adjusted proportionallyfor each type of electrosurgical procedure to be performed by the tool.For example, a user can increase or decrease a master energy level whichcorrespondingly increases or decreases the energy levels supplied to youelectrosurgical operation performed by the tool, which can be reflectedin the bar graphs 494, 496, 498 on the display 420. In anotherconfiguration, energy levels for electrosurgical tool can be manipulatedin a procedure-specific manner. For example, a user can increase ordecrease in energy level corresponding to one of the electrosurgicalprocedures performed by specific electrosurgical tool while leavingenergy levels for other electrosurgical procedures unchanged. Thischange can be reflected in one of the bar graphs on the display 420, forexample, the cut bar graph 494.

Electrosurgical System Phase Angle Operation

Electrosurgical Unit

Generally, an electrosurgical unit is provided that includes anelectrosurgical generator, an electrosurgical controller and one or moreelectrosurgical tool. The controller can be incorporated in or attachedto the generator with the tool attached to the controller.

In one embodiment, a controller is attachable to various electrosurgicalgenerators. The generator attached to the controller provides the supplyof RF energy as directed by the controller. The controller providesfeedback control and preprogrammed settings for the various attachablegenerators. This is largely enabled by using an internal measurementsignal that is independent from the attached generator. In other words,regardless of the driving frequency of the drive signal the generatorgenerates (which has an impact on the end point measurement, e.g., thephase shift), the measurement signal and hence the final phase shiftremains the same.

Referring to FIG. 5, in one embodiment, an electrosurgical generatorincludes an RF amplifier, pulse width modulator (PWM) and relays. Theelectrosurgical generator is coupled to a 120 Hz Voltage main input. Themain input is isolated with a low leakage isolation transformer of apower supply 631. The power supply provides operational voltages for thecontrol processor 637 and the RF amplifier 633. Additionally, the powersupply includes two 50 VDC output modules connected in series to providea total output of 100 VDC and 8 Amps. RF power is generated by the RFamplifier, e.g., a switched mode low impedance RF generator thatproduces the RF output voltage. In one embodiment, a 600 peak cutvoltage for cutting and 10 Amp current for coagulation/fusing isgenerated.

Fusing tissue in one embodiment involves applying RF current to arelatively large piece of tissue. Because of the potentially large toolcontact area tissue impedance is very low. Accordingly, to deliver aneffective amount of RF power, the current capability of the RF amplifieris large. As such, where a typical generator might be capable of 2 to 3amps of current, the RF amplifier of the generator can supply more than5 Amps RMS into low impedance loads. This results in rapid tissue fusionwith minimal damage to adjacent tissue.

The RF amplifier circuitry has redundant voltage and current monitoring.One set of voltage and current sensors are connected to the PWMcircuitry and are used for servo control. The voltage and current canalso be read by the processor 637 using an analog to digital converter(ADC) located on the PWM circuitry. The PWM circuitry also has an analogmultiplier, which calculates power by computing the product of thevoltage and current. The PWM circuitry uses the average value of voltageand current and does not include a phase angle and thus is actuallycalculating Volt Amps Reactive (VAR) rather than actual power. A secondset of voltage and current sensors are also connected to the Telemetrycircuitry 642. The signals are connected to an ADC for redundantmonitoring of the voltage and current. The processor multiplies thevoltage and current readings to verity that power output does not exceed400 Watts. The Telemetry circuitry has monitoring circuits that arecompletely independent of the PWM circuitry. This includes the ADC,which has an independent voltage reference.

The RF amplifier in one embodiment is a switching class D push pullcircuitry. As such, the amplifier can generate large RF voltages into ahigh tissue impedance, as well as large RF currents into low tissueimpedance. The output level of the RF amplifier is controlled by PulseWidth Modulation (PWM). This high voltage PWM output signal is turnedinto a sine wave by a low pass filter on the RF amplifier. The output ofthe filter is the coagulation output of the RF amplifier. The output isalso stepped up in voltage by an output transformer resulting in the cutoutput of the RF amplifier. Only one output is connected to the controlservo on the PWM circuitry at a time and only one output is selected foruse at a time.

Coupled to the RF amplifier is the PWM circuitry 634. The PWM 634 in oneembodiment receives voltage and current set points, which are input bythe user through a user interface, to set the output level of the RFamplifier. The user sets points are translated into the operating levelsby digital to analog converters of the PWM. The user sets points aretranslated into the operating levels by digital to analog converters ofthe PWM. The set points in one embodiment include a maximum voltageoutput, maximum current output, maximum power output, and a phase stop.The servo circuit of the PWM circuitry controls the RF output based onthe three set points. The servo circuit as such controls the outputvoltage of the RF amplifier so that the voltage, current, and power setpoints are not exceeded. For example, the output of the ESG isrestricted to be less than 400 watts. The individual voltage and currentset point can be set to exceed 400 watts depending on the tissueimpedance. The power servo however limits the power output to less than400 watts.

The RF output voltage and current are regulated by a feedback controlsystem. The output voltage and current are compared to set point valuesand the output voltage is adjusted to maintain the commanded output. TheRF output is limited to 400 Watts. Two tool connections are supported byusing relays 635 to multiplex the RF output and control signals. The EMIline filter 636 limits the RF leakage current by the use of an RFisolation transformer and coupling capacitors.

The cut and coagulation output voltages of the RF amplifier areconnected to the relay circuitry 635. The relay circuitry in oneembodiment contains a relay matrix, which steers the RF amplifiersoutput to one of the three output ports of the electrosurgical unit. Therelay matrix also selects the configuration of the tool electrodes. TheRF output is always switched off before relays are switched to preventdamage to the relay contacts. To mitigate against stuck relays steeringRF to an idle output port each output port has a leakage current sensor.The sensor looks for unbalanced RF currents, such as a current leavingone tool port and returning through another tool port. The currentsensors on are located on the Relay PCB, and the detectors and ADC areon the Telemetry PCB. The CPU monitors the ADC for leakage currents. Anyfault detected results in an alarm condition that turns off RF power.

The relay circuitry also contains a low voltage network analyzer circuitused to measure tool impedance before RF power is turned on. The circuitmeasures impedance and tissue phase angle. The processor 637 uses theimpedance measurement to see if the tool is short-circuited. If a Tool Aor B output is shorted the system warns the user and will not turn on RFpower. The RF amplifier is fully protected against short circuits.Depending on the servo settings the system can operate normally into ashort circuit, and not cause a fault condition.

Voltage and current feedback is provided using isolation transformers toinsure low leakage current. The control processor 637 computes the poweroutput of the RF amplifier and compares it to the power set point, whichin one embodiment is input by the user. The processor also monitors thephase lag or difference between current and voltage. Additionally, inone embodiment, the processor matches the different phase settings,which depend on tissue types to the monitored phase difference. Theprocessor as such measures a phase shift of tissue prior to anyapplication of RF energy. As will be described in greater detail below,the phase measurement is proportional to tissue permeability andconductivity that uniquely identifies the tissue type. Once the tissuetype is identified, the phase angle associated with an end pointdetermination of that tissue type can be determined. The generator inone embodiment has three RF output ports (Tool A, Tool B and genericbipolar). The tool A and B ports 639 are used to connect smart tools,while the generic bipolar port 640 supports standard electro surgicaltools. Audible tones are produced when the RF output is active or analarm condition exists.

The hand and foot controls are also isolated to limit leakage current.The control processor checks the inputs for valid selections beforeenabling the RF output. When two control inputs from the switches aresimultaneously activated the RF output is turned off and an alarm isgenerated. Digital to analog converters are used to translate controloutputs into signals useable by the Analog Servo Control. The controlset points are output voltage and current. The analog to digitalconverter is used to process the analog phase angle measurement. VoltageRMS, current RMS, and power RMS information from the controller is alsoconverted into a form usable for presentation to the user. The digitalI/O bus interface 638 provides digital communication between the user,controller and hand/foot switches. Isolation circuitry is used toeliminate a possible leakage path from the electrosurgical generator. Italso provides communication between the user and the generator though adata channel protocol.

In one embodiment, there are four tool Interface circuits in the unit.These circuits are used to electrically isolate the user input switchesfrom mains power inside the system. The four tool interface circuits areidentical and have an on board microprocessor to read the user switchinputs as well as the tool crypto memory and script memories. The switchclosure resistance is measured with an ADC to eliminate a contaminatedswitch contact being read as a closure. Switch closures below 300 Ohmsare valid, while any reading above 1000 Ohms is open. Readings between300 and 1000 Ohms are considered to be faulty inputs.

The four tool interface circuits communicate with the processor using anRS485 network. Each tool interface circuit has jumpers to select itsaddress and location in the unit. The RS485 interface is isolated toeliminate any potential leakage current paths. One tool interfacecircuit is connected to each of the Tool A and B ports. A third toolinterface circuit is connected to the DC output port, and the fourthcircuit is connected to the rear panel foot switch inputs. The processoris the network master and each of the four circuits is a network slave.The processor polls each circuit for input. The tool interface circuitrycan only reply to commands. This makes the network deterministic andprevents any kind of dead lock. Each Tool Interface circuit is connectedto a System OK logic signal. If a system error is detected by a ToolInterface circuit, this signal is asserted. The processor monitors thissignal and indicates a fault. This signal also has a hardware connectionto the PWM circuit and will disable the RF amplifier when asserted. Asystem error could be two input switches activated at the same time, ora loss of communication with the processor. The Tool A & B ports as wellas the DC port have a micro switch that detects when a tool is pluggedinto the receptacle. Until this switch is depressed the Tool Interfacecircuit front panel connections are configured off to prevent anyleakage current flowing from front panel connections. Once the switch isdepressed the Tool Interface allows the processor to initiate reads andwrites to the tool crypto memory and script memory. Once a tool isdetected a window opens in the user interface display showing the typeof tool connected and status. The generic bipolar port supports legacytools, which do not have any configuration memory. The tissuemeasurement circuitry is used to monitor the bipolar connectioncontacts. When a bipolar tool is connected the tool capacitance isdetected and the processor opens the bipolar tool window on the userinterface display and shows status for the bipolar tool. The DC port isused to interface with 12 Volt DC powered custom surgical tools. When atool is plugged into this port a window opens in the user interfacedisplay showing the type of tool connected and status. When the DC toolscript commands power on, the processor closes a relay on the PowerControl and Isolation circuitry 643 turning on the isolated 12 Volt toolpower.

The power control and isolation circuitry 643 has two other features. Itcontrols the 100 Volt power supply that drives the RF amplifier. Thispower supply is turned on by a relay controlled from the PWM circuitry.The processor commands this power supply on via the PWM circuitry. Ifthe PWM circuitry is reset or detects a fault condition, the relay willnot operate leaving the 100 Volt power supply off. Also located on thepower control and isolation circuitry is a RS485 isolation circuit thatadds an extra layer of isolation.

The front panel interface circuitry 641 is used to connect the frontpanel control switches and LCD display to the processor. The front panelinterface circuitry also contains a microprocessor, which is powered byan isolated standby power supply, which is on whenever the main powerswitch is on. When the front panel power switch is pressed, themicroprocessor uses a relay on the Power Control and Isolation circuitryto turn on the main logic power supply. When the button is pressed toturn power off, the microprocessor signals a power off request to theprocessor. When the processor is ready for power to be turned off itsignals the microprocessor to turn off power. The power control relay isthen opened, turning off the main power supply.

In one embodiment, the generator accepts only single switch inputcommands. With no RF active, e.g., RF energy applied, multiple switchclosures, either from a footswitch, tool, or a combination of footswitchand tool are ignored. With RF active, dual closures shall cause an alarmand RF shall be terminated. The footswitch in one embodiment includesmomentary switches providing activation of the application of RF energy.The switches for example when manipulated initiates activation of the RFenergy for coagulation, for cutting and/or sequenced coagulation orcutting. A two-position pushbutton on the foot pedal switch allowstoggling between different tools. The active port is indicated on thedisplay of the generator and an LED on the hand tool.

In one embodiment, all RF activation results in a RF ON Tone. Activationtone volume is adjustable, between 40 dBA (minimum) and 65 dB (maximum)with a rear panel mounted control knob. The volume control however doesnot affect audio volume for alarms. Also, in one embodiment, a universalinput power supply is coupled to the generator and operates over theinput voltage and frequency range without the use of switches orsettings. A programming port in one embodiment is used to download codeto the generator and is used to upload operational data.

The generator in one embodiment provides output power has a 12V DC at 3Amps. Examples of such tools that use DC power are, but are not limitedto, a suction/irrigation pump, stapler, and a morcellator (tool fordividing into small pieces and removing, such as a tumor, etc.). The DCconnector has intuitive one-way connection. Similar to the other toolreceptacles, a non-sterile electronic chip module is imparted into theconnector of the appropriate DC-powered hand tool by a one-time, one-waylocking mechanism. Tool-specific engravings on both the connector andchip module ensure that the chip module fits only to the type of toolfor which it has been programmed. The chip connector allows toolrecognition and the storage of data on tool utilization. The DCconnector is also configured to prevent improper insertion. Thegenerator is also configured to recognize the attached DC-powered tool.The generator reads configuration data from the tool connector, allowingtool recognition and the storage of tool utilization data.

The controller in one embodiment recognizes the tool upon the tool beingattached to the controller. Based on the recognized tool, the generatoraccesses and initiates specific operations and setting parametersutilized to configure the controller to properly apply RF energy asdesired by the tool. For example, parameters set includes but notlimited to an automatic preset of the output voltage, activation ofspecific output pins (connected to tool) or determination of thefeedback cycle.

In one embodiment, the controller supplies control signals and/or powerto a connected tool to indicate when they are active via a LED and/or adistinctive audio tone. The controller is also arranged to display whenand/or which specific tool is active. The controller also prevents thetool from being reused after certain expiration of the tool shelf life,or a specific time period after the first tool activation.

In one embodiment, phase measurement is a relative measurement betweentwo sinusoidal signals. One signal is used as a reference, and the phaseshift is measured relative to that reference. Since the signals are timevarying, the measurement cannot be done instantaneously. The signalsmust be monitored long enough so that difference between them can bedetermined. Typically the time difference between two know points (sinewave cross through zero) are measured to determine the phase angle. Inthe case of the phase controller, the device makes the output sine wavewith a precise crystal controlled clock. That exact same clock is use toread the input samples with the analog to digital converter. In this waythe output of the phased controller is exactly in phase with the inputof the phase controller. The phase controller in one embodiment comparesthe input sine wave signal to a reference sine wave to determine theamount of phase shift.

The phase controller does this comparison using a mathematical processknown as a Discreet Fourier Transform (DFT). In this particular case1024 samples of the input signal are correlated point by point with botha sine function, and a cosine function. By convention the cosine part iscalled real, and the sine part is called imaginary. If the input signalhas no phase shift the result of the DFT is 100% real. If the inputsignal has a 90-degree phase shift the result of the DFT is 100%imaginary. If the result of the DFT has both a real and imaginarycomponent, the phase angle can be calculated as the arctangent of ratioof the imaginary and real values.

It should be appreciated that the phase angle calculation is independentof units of the real and imaginary numbers. Only the ratio matters. Thephase results of the phase controller are also independent of gain andno calculation of impedance is made in the process of calculating thephase angle. By performing a DFT, the phase controller encodes the phasemeasurement as a pair of numbers.

A user interacts with the electrosurgical unit via a graphical paneldisplay and associated switches 641. The front panel switches allowinteraction with LCD display menus generated on the graphical paneldisplay. The menus allow language selection, and modification of toolset points. In one embodiment, only when a tool is plugged in anddetected by the unit, parameters can be changed for that tool.

The electrosurgical unit as described above includes one or morereceptacles in which electrosurgical tools connect to the unit. Throughthis connection, a tool and unit communicate with each other. Connectingthe tool also causes the controller to update the display of the systemto show tool information and current intensity.

An example of a display or user interface 641 is shown in FIG. 6. Theuser interface provides tool information such as tool status for eachconnected tool and allows a user to modify set points, e.g., theapplication or intensity of the RF energy. The user interface in oneembodiment also shows the tool settings for functions for each connectedtool. In the illustrated embodiment, three tools are connected to thegenerator. Accordingly, a suction/irrigation pump display 621, a Kiifusion tool display 622 and a spatula tool display 623 are shown.Associated operations or actions available for each tool are alsoprovided in which the suction/irrigation pump has an on/off setting 624;the Kii fusion tool has relative power settings for cut 625, coagulation626 and fuse 627; and the spatula tool has relative power settings forcut 628 and coagulation 629.

In one embodiment, the user interface allows a simultaneous change toall settings for a selected tool (indicated by the highlighted rim 631)by pushing single button from the navigation buttons 632. For example,as shown in FIG. 7, pushing the “up” button 633 will simultaneouslychange the cut, coagulation and fuse relative power settings for theconnected Kii fusion tool. Additionally, the settings can be changedindividually by navigating into a sub menu, as shown in FIG. 8. In theillustrated case, the coagulation level of the Kii fusion tool ischanged without changing the cut and/or fuse relative power setting. Byselecting the default button 634, the settings for all tool functions ofthe selected tool are returned to the default setting. Also, aswarranted by the context, an associated button operation andcorresponding label can vary as shown in button 635 being a menu buttonin FIG. 7 and a back button in FIG. 8.

A block diagram illustrating a controller in accordance with variousaspects of the invention is shown in FIG. 9. As shown, the output of agenerator is fed into circuitry that determines the frequency of thedriving signal and circuitry to measure the phase shift between voltageand current applied to the tissue. The voltage applied by the generatoris sent through a buffer/level shifter 541 that reduces the amplitude ofthe output voltage. The signal is processed to deliver the frequency ofthe generator output via frequency measurement 542 and fed into amicrocontroller 543. The frequency of the driving signal can directlyimpact the phase shift. Similarly, the generator output is sent througha signal conditioning circuitry 544 to reduce high-frequency noise, andthen conditioned via voltage and current conditioning 545 a-b andfiltered by multi-pole low pass filter 546 a-b to deliver signals torepresent applied voltage and current. Both signals representing voltageand current are measured for phase shift using a phase comparator 547.The output of the phase comparator is fed into the microcontroller 543.Depending on the frequency of the electrosurgical unit used, which candetermine the final phase shift to be reached, the microcontrollercompares the output of the phase comparator with the trigger leveldetermined by the driving frequency of the generator. When such triggerlevel is achieved, i.e., the tissue fusion or welding is completed, themicrocontroller 543 causes the tissue to be disconnected from thegenerator and indicates that state by acoustical or visual indicators548 (buzzer, display, lights, etc.). An over-voltage detector 549 isalso provided that is supplied the generator output to detect excessivevoltage the condition of which is supplied to the microcontroller 543.

FIG. 10 shows a block diagram of a controller in accordance with variousembodiments of electrosurgical unit utilizing the phase shift betweenvoltage and current to determine the end-point of the fusion process. Amicrocontroller 553 delivers a low-voltage square-wave signal 551 at 5MHz, which is converted by a 4-pole low pass filter 550 into alow-voltage sin-wave signal 552 at 5 MHz. The low-voltage 5 MHz signalis superimposed to the output of the generator, which is typically inthe 100 to 200V range at frequencies of 300 to 500 kHz. As an example,the superimposed voltage signal of a 200V driving voltage at 500 kHz anda 5V measurement voltage at 5 MHz is shown in FIG. 11.

The combined voltages are then applied to the tissue and, just as in theprevious example, also conditioned through a buffer/level shiftercircuitry for processing. Similarly, the current through the tissue ismeasured and also conditioned for processing. The processed voltage (andcurrent) signal containing the high voltage (and high current) signal at300 to 500 kHz from the ESU, as well as low voltage (low current) signalat 5 MHz are sent through a multi-pole band pass filter centering at 5MHz. The filter discriminates the signal from the ESU, leaving only thetwo signals at 5 MHz for measuring the phase shift in a phasecomparator. The filtered signals for both the voltage and current at 5MHz are illustrated in FIG. 12 at a time near the end of the fusionprocess.

The measured phase shift is fed into a microcontroller, which comparesthe reading with a pre-determined level indicative to the completion ofthe fusion process at 5 MHz frequency. Again, when such a trigger levelis achieved, i.e., the tissue fusion or welding is completed, themicrocontroller 553 will cause the tissue to be discontinued from thegenerator and indicate that state by acoustical or visual indicator 548(buzzer, display, lights, etc.).

FIG. 13 shows a schematic block diagram of one aspect of a controller.As shown, a microprocessor 561 times the switching of the tissue betweenthe output of a generator and an internal measurement circuit. As aresult, the tissue is periodically assessed for the status of the fusionprocess by measuring the phase shift of a low-voltage and low-currentmeasurement signal. Depending on the value of the obtained phase shift,the tissue is either switched back to the high-voltage output of thegenerator for further fusion, or permanently disconnected from thegenerator. As such, the internal circuit comprises of a microprocessor561 generating a low-voltage square wave signal 562 at 500 kHz that istransferred into a low-voltage sinusoidal wave 563 at 500 kHz. Thissignal is applied to the tissue, and analyzed by a phase comparator 564only when it electrically disconnected from the generator during regularmeasurement intervals.

In one embodiment, the phase shift is derived directly from the drivingsignal, i.e., the voltage and current supplied by the electrosurgicalgenerator to the tissue. In one embodiment, an electrical circuitmodifies the driving voltage having one (sinusoidal) frequency bysuperimposing a measurement signal at a vastly different frequency. As aresult, electrical energy for the fusion process is provided at onefrequency, while simultaneously applying as second signal at a secondfrequency for measurement. Separation of the two different signals byusing band pass filters in the measurement circuit allows continuousmeasurement of the phase shift during the electrosurgical fusion orwelding process. In one embodiment, the controller periodicallyinterrupts the supply of electrosurgical energy to assess the status ofthe fusion or welding process by applying a low-voltage measurementsignal. Depending on the phase shift obtained during the measurementcycle, the controller switches the driving signal from the generatorback to the tissue or isolates the tissue. In one embodiment, thecontroller interrupts the tissue fusion or welding process at apre-determined level of phase shift by terminating the supply of RFenergy from the generator to the tissue.

FIG. 14 depicts a controller or control unit in accordance with aspectsof the present invention for the controlled fusion or welding ofbiological tissue. As shown, the control unit is connecting the bipolarpower outlet of a generator 507 to the tool 508 that is arranged tocompress vessels or tissue. The tool also houses a switch 509 thatactivates the fusion process. If the generator is equipped with an inputfor hand activation (rather than using a foot pedal 511 or otherintermediary device), a third connection 512 from the control unit tothe generator allows activation of the generator with the same handswitch.

The controller in one embodiment includes a processor 513 that controlsthe switching of the tissue between the direct output of the generatorand an internal measurement circuit, e.g., switch 515. It is poweredwith an internal battery power module 514. The timed switching causesthe tissue to be fused in intervals while periodically measuring thestatus of the tissue. As such, the measurement signal is a 500 kHzsinusoidal low voltage signal, generated by a signal generator 518 whenfed with a 500 kHz square wave from the microprocessor 513. When thelow-voltage sinusoidal measurement signal is applied to the tissue, aphase comparator 516 measures the phase shift between the appliedmeasurement voltage and the current caused by application of themeasurement voltage. Depending on the result analyzed or processed bythe processor, the tissue will be either be switched back to thegenerator, or disconnected from the generator accompanied by anacoustical and/or visual indication via LEDs/buzzers 517.

FIG. 15 shows in one embodiment of the external measurement circuit thatgenerates the low-voltage sinusoidal signal used to measure the phaseshift. It is generated by passing a 500 kHz square wave through a 4-polelow-pass active filter 531. The 4-pole low pass filter removes higherharmonic components and passes the sinusoidal fundamental frequency. The500 KHz square wave is generated via the PWM peripheral 522 in themicrocontroller 524.

FIG. 16 illustrates switch 515 configured to switch between theapplication of the drive signal and the measurement signal, e.g., the500 kHz, 5 Volt peak-to-peak sine wave reference signal, from thegenerator. Although the use of a solid-state switch to implement theswitching offers a long operational life and inherent current surgecontrol, it can be difficult to block the relatively high voltage (−200VAC) and high frequency (−500 KHz) signal generated by a typicalgenerator in bipolar coagulation mode. As such, two double pole,double-throw mechanical relays 527,528 are used. The first relay 527switches between the generator and the reference signal. The secondrelay 528 limits the current surge, which can damage the relay andcreate an electromagnetic interference (EMI) pulse that can disrupt thelow-voltage circuitry. Additionally, this protects the tissue againstcomplications or issues caused by electrical arcing. Since mostgenerators are constant power devices, the highest voltages occur duringconditions of no load. By first switching in the generator through aseries resistor, the output voltage of the generator is shared acrossthe resistor, limiting the voltage imparted to the tissue. Furthermore,the resistor serves as an energy limiter, enabling high conductivechannels in the tissue to fuse before the full power of the generator isapplied.

In one embodiment, switching takes place in the following sequence. Whenswitching from the low voltage measurement or reference signal to thegenerator, the first relay 528 switches out both ends of the referenceand switches in one generator lead directly and one through a 100 Ohmresistor. The 100 Ohm resistor limits the surge current to two amps fora 200 Volt source. If a shorted output occurs, 400 watts are dissipatedin the 3 Watt resistor, which would quickly burn up. However,approximately 50 milliseconds after the first relay 528 switches in thegenerator, a second relay 527 switches out the 100 Ohm resistor, keepingit from burning up and allowing the full power of the generator to bedelivered to the tissue. When the device switches the other way (fromthe ESU to the reference signal), it first switches in the 100 Ohmresistor, reducing the current, and then switches out the generatorentirely. This sequence reduces inductive kickback and EMI generation.

The relays 527,528 in one embodiment are of a latching type. Mostmechanical relays draw a fair amount of power in their non-default state(an electrical current is needed to fight the force of the returningspring). Since the controller is equipped with a battery of limitedpower capacity, two latching type relays are used. These relays only usecurrent to transition between two stable states and can operate at amuch lower power level.

The phase detection circuitry 530 is shown in FIG. 17, which measuresthe phase shift between the two above-mentioned sine waves. The firstpart of the circuit level-shifts the sine wave to the same DC value as areference voltage. The level-shifted signal is then sent to the negativeinput of a comparator 531. The positive input is connected directly tothe DC reference voltage. A small amount of hysteresis is used to reduceswitching noise. The output of the comparator is a square wave with thesame phase as the input sine wave. These two signals are sent to anexclusive “OR” gate 532. The output of the gate is high when one of thetwo inputs is high, and low otherwise. The duty cycle of the output istherefore linearly related to the phase of the two input square waves.The duty cycle is converted to a DC voltage through a low pass filter,which is measured by the analog to digital converter peripheral of themicrocontroller.

FIG. 18 shows the battery power circuit that is powering the controlcircuit by two low-capacity coin cells. The battery provides a life of500 fusing cycles over a 5-hour time span. When a specific number ofseals, or a specific time limit have been reached, the controller issuesa warning and ceases operating. The controller manages its power demandaround the power characteristics of the specific batteries used. Thecontroller includes management controls that prevent specific operationsfrom occurring simultaneously that may exceed the power capacity of thebatteries, power down selected portions of the circuit between fusingcycles, and slow the microcontroller oscillator down from 4 MHz to 32kHz between fusing cycles.

FIG. 19 shows an input port 534 adapted for connecting to a tool. Withengagement of a switch on the tool, the controller takes initialmeasurements on the tissue (shorting, etc.) and based on the initialmeasurements activates the generator to supply electrosurgical powerthat is passed and controlled by the controller.

As many generators can exclusively (but also alternatively, with thesurgeons preference) be activated with a foot-pedal, the controlleraccommodates such a scenario. For example, if the generator is activatedwith a foot switch while subsequent activation of the hand switch on thetool occurs, the controller allows switching-in of the output of thegenerator.

The result of using the control circuit described above is shown in FIG.20, showing the effective voltage applied to the biological tissue asfunction of time. As shown in this specific example of porcine renalarteries, the tissue is being exposed to 6 high-power fusion intervalsof about 850 ms time duration, interrupted by 5 measurement cycles ofabout 300 ms.

In one embodiment, the fusion process starts with depressing a switch onthe tool, which starts an initial measurement sequence. This point intime is marked start (switch on) 535. The tool in one embodiment checksthe resistance between the two electrodes and if the phase shift iswithin an acceptable range. Verifying the phase shift prevents anattempt to re-fuse already fused tissue. Based on the results of theinitial check, the controller switches-in the activated output of thegenerator to the tissue. This starts the application of RF energy to thecompressed tissue. After about 850 ms, the controller disconnects thetissue from the generator and switches back to the first tissueassessment phase. Depending on the result, the tissue gets heatedfurther, or remains disconnected from the generator to remain on themeasurement circuit. The latter case is marked “power stop (switch on)”536. In this case, an acoustical and/or visual signal is given off theunit, indicated that the tissue is sealed (or that shorting of theelectrodes has occurred). The supply of the measurement signal to thetissue is ended when the switch on the tool is released, marked “manualstop (switch off)” 537. At this point, all supply of energy to thetissue is terminated.

A more detailed analysis of the measurement cycle 538 is shown in FIGS.21 and 22, showing that additional measurements (other than the phaseshift) can be included in that measurement period. Such measurements,for example, could prevent attempting to fuse already fused tissue, orpowering of electrically shorted electrodes.

In FIG. 22, a more detailed analysis of the measurement plateau 539 of2V in FIG. 21. As shown, a detailed view of the low-voltage measurementsignal 540 at 500 kHz used to determine the phase shift through thetissue during the RF measurement cycle.

Electrosurgical Systems and Processes

Electrosurgical systems and processes in various embodiments applymonopolar or bipolar high-frequency electrical energy to a patientduring surgery. Such systems and processes are particularly adapted forlaparoscopic and endoscopic surgeries, where spatially limited accessand visibility call for simple handling, and are used to fuse bloodvessels and weld other biological tissue and in one aspect to cut,dissect and separate tissue/vessels. In particular embodiments, thesystems and processes include the application of RF energy tomechanically compressed tissue to (a) desiccate the tissue, and (b) todenature collagens (type I-III) and other proteins, which are abundantin most biological tissue. As heating of collagens to an appropriatetemperature causes them to unfold, shrink or denature, the systemenables the sealing of capillaries and blood vessels during surgery forpermanent occlusion of the vessels. As described in greater detailbelow, as an example, arteries up to seven millimeters can be occludedand dissected by radio frequency (RF) energy and mechanical pressure.

When concurrently applying controlled high-frequency electrical energyto the compressed tissue, the tissue is compressed with a relativelyhigh pressure (about 10-20 kg/cm2), and the tissue is supplied withsufficient electrical energy to denature proteins and remove sufficientwater in the tissue. During this process, the applied voltages aresufficiently reduced to avoid electrical arcing (typically <200V RMS).

When applying electrical energy in the described manner stated above,the tissue quickly moves through the following fusion/welding process.Starting at body temperature the tissue (a) heats quickly, leading to(b) cell rupture, expelling of juices (mainly water and salt ions), (c)unraveling and “activation” of collagens and elastin in the bloodvessels at about 60-650 C, and (d) desiccation of the vessel. Here, thedesiccation process can be seen by the release of water in form of steamwhere the vessel temperature has reached about 1000 C. The reduction ofwater in presence of unraveled collagen and elastin strands leads toformation of bonds between collagen strands, leading to a strong andelastic seal of the tissue. As confirmed by measurements, the strongest(highest burst pressure) vessel fusions are obtained when the vesselshave been heated to at least 70° C., pressurized with about 10-20kg/cm2, and then desiccated by about 40-50% of their original watercontent.

Electrically, the tissue can be characterized during the fusion processby its impedance, which is typically starting at 10-100 Ohms purelyohmic resistance. During the fusion process, the purely ohmic resistancereduces by 20-50% before it increases by two orders of magnitude. As theresistance approaches a final value, the impedance of the tissuegradually increases in capacitive behavior with a phase shift of about20 degrees. The tissue will exhibit a pronounced capacitive behavior atthe end of the fusion process with a phase shift of about 40 degrees,even though the ohmic component will remain nearly unchanged during thisphase.

Referring now to FIG. 23, graphical representation exemplifyingexperimental data for the sealing of a four-millimeter diameter porcinerenal artery in accordance with various embodiments of electrosurgicalsystem is shown. The fusion process is performed by compressing theartery with 0.75 millimeter wide electrodes with a compression load ofthree pounds, and by energizing it with a voltage-stabilizedelectrosurgical power supply using 200V at 60 W maximum power setting.Voltage 501, current 502 and electrical power 503 in the beginning ofthe fusion process (1 second) are shown. As can be seen, the sinusoidalvoltage and current are substantially in-phase, e.g., the phasedifference or angle equals zero. At this time, the impedance of theartery is purely ohmic with a value of about 100 Ohms.

The temporal progression of the applied peak voltage and peak currentfor the same-sized artery is provided in FIG. 24. The applied voltagequickly stabilizes to a constant value, which is an artifact of thevoltage-stabilized power supply. Regardless of the applied load,voltage-stabilized electrosurgical power supplies regulate the outputvoltage to a pre-set value since the voltage has a dominant impact onthe electrosurgical effect. In contrast to the voltage, the currentdriven through the artery increases from an initial 1 A to 1.5 A at 0.5s, and then gradually reduces over the next three seconds to about 0.2A. For the remaining 4 seconds of the fusion time the peak value of thecurrent remains nearly unchanged.

Another way to depict the information from FIG. 24 is shown in FIG. 25,showing the impedance 506 of the artery as function of fusion time. Theinitial impedance of the harvested artery is 75 Ohms. With applicationof high frequency electrical energy the artery heats quickly, leading toshrinkage of collagens, rupture of cell membranes, and the ultimateexpelling of trapped liquid (mainly water and ions). As a result, theimpedance has reduced to about 54 Ohms. Further supply of electricalenergy starts to desiccate the artery, resulting in an impedanceincrease. At about 4 seconds into the fusion process the impedance ofthe artery starts to stabilize, with a slow increase of the impedancefrom about 800 Ohms to about 1,200 Ohms.

The fusion process could be terminated (a) at a fixed and absoluteresistance (for example 2 k Ohms), which would neglect both the size andtype of tissue, (b) at a specific multiple of the time where the ohmicresistance is minimal, (c) at a specific multiple of the time where theohmic resistance is the same as the initial one, or (d) at a specificmultiple of the time where the ohmic resistance is a certain factor ofthe minimal one. However, considering burst pressure of fused arteriesand thermal spread, the termination of the fusion process is determinedto be in the flattened part of the impedance curve. As can be seen inFIG. 25, however, this region is also an inexact range for impedancemeasurements. Similarly, each succession of (a) to (d) becomes better indetermining the end-point of the fusion time (resulting in the highestdesired bursting pressure with the least desired thermal spread).Utilizing the ohmic resistance only as termination criterion can lead toincomplete results. This can be more pronounced when fusing differentlysized tissues (even of same nature), also exemplified in FIG. 26 showingthe relative resistance (relative to the initial resistance) ofvarious-sized arteries and other tissue as a function of fusion time.

Termination of the fusion process for same-material tissue (i.e.,arteries) cannot be controlled with desired precision by specifying onerelative ohmic load (e.g., when the resistance reaches 3 times theinitial resistance). Instead, the relative change in resistance dependson the size of the vessel, i.e., <2 mm arteries seal in fractions of asecond (where the resistance about doubles compared to the initialresistance), about 3 mm arteries seal in about 2 seconds (where theresistance about triples), and 15 mm arteries/veins seal in about 7seconds (where the resistance increases by a factor of 5). At the sametime, some arteries may not follow that characterization (e.g., a 3-4 mmartery would not reach more than 2.5 times the initial resistance).Instead, the fusion process should end within the flat region in FIG.25. As previously described, precision is difficult in the flat regionwith the function of time at different fusion times.

Phase Based Monitoring

In one aspect, the determination of the end-point of the fusion processis given by monitoring the phase shift of voltage and current during thefusion process. Unlike impedance, the phase shift changes much morepronounced at times where the artery desiccates and the fusioncompletes, and hence offers a more sensitive control value than theimpedance. This can be seen when monitoring the voltage and current asfunction of time at different fusion times, as is shown in FIG. 23 forthe beginning of the fusion process.

In FIG. 23, the beginning of the fusion shows that the applied voltageand current are in phase (with a shift of about −3 degrees), revealingthat the artery behaves dominantly like an ohmic load of about 75 ohms.Further supply of energy leads to heating of the artery, an initialreduction in impedance (caused by shrinking of collagens, cell membranerupture and expelling of mainly water and dissolved ions), and asubsequent increase in impedance. During this period of vessel fusion,the phase difference between voltage and current remains small withminimal changes, indicating that the artery is purely ohmic.

The artery is not fully desiccated, and thus the seal is not complete.Referring to FIG. 27, at 4 seconds into the fusion process, the phasedifference slowly increases to −10 degrees (current leads). Whilefurther supply of electrical energy does not significantly change thevalue of the resistance (see FIG. 24), it does cause a pronouncedincrease in phase difference between voltage and current. This can beseen in FIG. 28 at 7 seconds into the fusion process, showing a phasedifference of about 25 degrees. The vessel fusion process continues andyields the desired burst pressures at the least desired thermal spreadwhen the phase difference or angle reaches about 35-40 degrees as shownin FIG. 29. Also, as shown the phase angle reaches about 20 to 40degrees. Similarly, the phase difference or angle necessary to result inwelding of other tissue reaches about 45-50 degrees for lung tissue, and60 to 65 degrees for small intestine. However, for all types of tissue,reaching a high end of the phase range can lead to excessively longsealing times. Accordingly, as will be described in greater detailbelow, the application of RF energy, i.e., drive signal, via anelectrosurgical generator in conjunction with the measuring ormonitoring of phase shift, i.e., a measurement signal, via anelectrosurgical controller are provided to fuse or weld vessels andtissue in accordance with various embodiments of electrosurgical system.

Endpoint Determination Based on Tissue Properties

Using the phase difference between voltage and current as a controlvalue in the fusion or welding process, instead of the impedance, can befurther shown when characterizing the tissue electrically. Whenconsidering vessels and tissue to be a time-dependant ohmic resistor Rand capacitor C in parallel (both of which depend on the tissue size andtype) the phase difference can be obtained with

${R = \frac{\rho \cdot d}{A}},$

where R is the ohmic resistance, ρ the specific resistance, A the area,and d the thickness of the fused tissue,

${X_{C} = \frac{1}{\omega \cdot C}},$

where X_(C) is the capacitive impedance, ω the frequency, and C thecapacity of the tissue, and

${C = \frac{ɛ \cdot ɛ_{0} \cdot A}{d}},$

where ∈ and ∈₀ are the relative and absolute permittivity.

The phase difference φ can then be expressed as

$\begin{matrix}{\phi = {\arctan \left( \frac{X_{C}}{R} \right)}} \\{= {{\arctan \left\lbrack \left( {\omega \cdot ɛ \cdot ɛ_{0} \cdot \rho} \right)^{- 1} \right\rbrack}.}}\end{matrix}$

As such, the difference between monitoring the phase difference φ asopposed to the (ohmic) resistance R is that φ depends on the appliedfrequency ω and material properties only (namely, the dielectricconstant ∈ and the conductivity ρ), but not on tissue dimensions (namelythe compressed tissue area A and tissue thickness d). Furthermore, therelative change in phase difference is much larger at the end of thefusion process than the change in tissue resistance, allowing for easierand more precise measurement.

In addition, with measurement of the initial dielectric properties ofthe tissue (dielectric constant ∈ and conductivity ρ) at a certainfrequency, the type of tissue can be determined. The dielectricproperties for various types of biological tissue, arranged byincreasing values of the product of dielectric constant ∈ andconductivity ρ) are given in FIG. 30 at a frequency of 350 kHz (which isin the frequency range of a typical electrosurgical generator). Bymeasurement of the product of dielectric constant and conductivity p ofthe tissue (which are material characteristics and independent of tissuedimensions) before the actual tissue fusion or welding process, thephase shift required to adequately fuse or seal the specific biologicaltissue can be determined from FIG. 30. The phase shift required toreliably fuse or seal the respective type of tissue is measured asfunction of the product of dielectric constant ∈ and conductivity ρ ofthe tissue (at 350 kHz). FIGS. 31 and 32 further emphasize this functionin which in FIG. 31, endpoint determination is shown as a function of aninitial phase reading and in FIG. 32, end point determination is shownas a function of tissue properties (conductivity times relativepermittivity). The function of tissue properties can also be expressedas φend=38+29 [1−exp(−0.0091 ρ∈)].

As a result, (a) measurement of the dielectric properties of the tissueand (b) control and feedback of the phase difference allows for aprecise control and feedback mechanism for various tissue types,regardless of the tissue size and allows employing standardelectrosurgical power supplies (which individually run in a very closerange of frequencies). It should be noted that however that specificfrequency of the tissue properties measurement is performed can be thesame or different from the specific frequency of the phase If the tissuemeasurement is based on the driving frequency of the generator, andvarious generators are used (all of which run in a close range offrequencies) though, the end points will be different. Hence, for such acase, it can be desirable to (1) use an external measurement signal(which is at the same frequency), or (b) utilize a stand-alonegenerator.

As such, the controller is configured to determine the product ofdielectric constant and conductivity, as well as the phase differencebetween the applied voltage and current to monitor and control thetissue fusion or welding process. In particular, control and feedbackcircuitry of the controller determines when the phase difference reachesthe phase shift value determined by the result of the dielectric andconductivity measurements. When this threshold is reached, the fusion orwelding process is terminated. An indicator, e.g., visual or audible, isprovided to signal the termination and in one aspect the controllerrestricts (completely, nearly completely or to a predetermined minimum)further delivery of electrical energy through the electrodes. As such,the tool generating the seal, weld or connection of the tissue providesatraumatic contact to the connecting tissue and provides enough burstpressure, tensile strength, or breaking strength within the tissue.

Capacitive Load Compensation of Connected Tools

In one embodiment, measuring and accounting for the tool capacitance andtool resistance is provided for consistent initial tissue assessment(conductivity and permittivity) which provides the tissue-specificendpoint of the process (i.e., coag, fuse, or weld). In another aspectof the invention, measuring and accounting for the tool capacitance andtool resistance is provided for consistent tissue feedback measurements(phase shift) which ensures consistent tissue modification results(i.e., coag, fuse or weld).

FIG. 33 shows phase diagrams of two electrosurgical tools. As can beseen, both tools are electrically represented as a resistive or ohmicload (originating mainly from the wire harness 1500 connecting the handtool to the generator, as well as the connections within the handtools), as well as a capacitive load (originating mainly from the tooljaws, as well as the wire harness 1500 connecting the hand tool to thegenerator). In a phase diagram, the tool can be characterized by a phaseangle □.

The values of the ohmic and capacitive impedances found in typicalarrangements of tools are in the range of 1-10 Ohms for the ohmic loadand 1-100 kOhms for capacitive resistances (several ten to severalhundred pF capacitance at several 100 kHz). Even for two equal toolsvariations in the tool characteristics (such as wire connections,harness length, etc.) can lead to different phase angles □ and □′ forthe same tool. As will be shown in the following, these variations canlead to different tissue measurement results, used both before andduring tissue assessment.

As shown in FIG. 34, the phase diagram of an electrosurgical tool thatis in contact with tissue composes of the resistive and capacitivecomponent of the tool (dotted arrows) which add to the ohmic andcapacitive component of the tissue (solid arrows) to present a totalload to the electrosurgical generator (dashed line). For tissuemeasurement techniques that rely on the phase shift of voltage andcurrent, the presence of the tool significantly alters the results ofthe intended tissue measurement by the apparent phase.

In this context, the presence of the tool (impedance) does not pose anactual problem if the tissue measurement before powering (to determineend point of fuse/weld), or during powering (to determine the end pointof the fuse/weld) has been defined with the very same tool (i.e., toolimpedance). Instead, variances of the tool impedances lead to differentresults in both the initial tissue assessment (pointing to an inaccurateendpoint) and tissue feedback measurement (determining the end point ofthe fuse/weld).

As such, the controller used to measure the phase shift during thetissue modification process can be used to initially determine theinitial tool impedance (e.g., during plug-in of the tool connector tothe electrosurgical generator), where tolerances/changes in the toolcharacteristics are then accounted for in the tissue measurementalgorithm. This will allow for tissue measurement values which areindependent of the ohmic and capacitive values and/or tolerances of thespecific electrosurgical tool.

Accordingly, generally speaking, when tool capacitance increases, theendpoint phase shift decreases. In particular, when the tool capacitanceincreases, the capacitive impedance decreases (X=1/ωC). Decreasedcapacitive impedance leads to a smaller or decreased end point phaseshift. Similarly, when tool resistance increases, the end point phaseshift decreases.

Also, from an initial tissue determination perspective, generallyspeaking, when tool capacitance increases, the apparent initial phaseshift decreases compared to the “ideal” value. The “ideal” value being atool having zero or near zero capacitance. Similarly, when toolresistance increases, the apparent initial phase shift decreasescompared to the “ideal” value. As such, when the tool capacitance(C=∈∈₀A/d) and/or the tool resistance (R=p d/A) increase, there is anincrease in permittivity and/or conductivity which reflects a decreasein tan φ, i.e., a decrease in phase. In one example, an electrosurgicaltool having a capacitance of 160 pF had an initial phase shift of 9-59degrees versus a tool having a capacitance of 230 pF having an initialphase shift of 6-23 degrees. Additionally with tissue permittivity andconductivity product values being inversely proportional with theinitial phase shift, when tool capacitance and/or resistance increases,the apparent tissue permittivity and conductivity product valueincreases compared to the “ideal” value.

FIG. 35 shows the ohmic resistance of a porcine renal artery during theelectrosurgical fusion process. As was shown previously, the fusionprocess of blood vessels and/or welding of tissue can be bettercontrolled when the phase difference or angle between applied voltageand incurred current is measured and used to interrupt thefusion/sealing process. Depending on the type of tissue, the end pointhas been found to be ideal at about 40 degrees (blood vessels) or 60degrees (intestines), respectively.

Instead of the tissue quickly reaching a pre-determined phase (rangingfrom 40 to 60 degrees, depending on type of tissue), the measured phaseshift approaches the cut-off threshold asymptotically. This is shown inFIG. 36 for the same seal as given in FIG. 35. As can be seen, the phaseshift quickly increases during the initial fusion process, but thenincreases slowly for the remainder of the seal. The asymptotic approachcan require a significant amount of time to reach the final phasethreshold (e.g., 40 degrees). As such, instead of depending on the phasevalue to reach a definite value alone, additionally the derivate of thephase can be used to avoid asymptotic approaches to a finalized phasevalue. The derivative of the phase value of the same seal is shown inFIG. 37. As shown, the phase changes (increases) strongly during thefirst 0.5 s into the seal and changes little for the remainder of theseal. After about 1.5 s sealing time, the derivative of the phase dφ/dtreaches a pre-determined value of 0.1 degrees/second to terminate theseal (independent of the actual phase reading).

Additionally, the determined phase value can be overshot without beingdetected, for example, when the phase trip level is reached during theread out time of the processor controlling the power supply. In suchcases, the processor may not recognize that the final phase stop hasbeen reached. This is shown in FIG. 38 for welding of porcineintestines. As can be seen, the phase shift overshoots a pre-determinedphase threshold of 60 degrees, but instead reaches an asymptoticsteady-state level of 50 degrees. Instead of relying on the phase valueto reach a definite value alone, the derivate of the phase is also usedto ensure the seal to end.

The derivative of the phase value of the same seal is shown in FIG. 39.As shown, the phase changes (increases) strongly during the first 0.25 sinto the weld and changes only little for the remainder of the seal. Atabout 1.5 s into the weld, the derivative of the phase dφ/dt reaches apre-determined value of 0.1 degrees/second and terminates the weld(independent of the actual phase reading). The derivate of the phase inone embodiment is set to 0.02 degrees per second. A range of phasederivate from 0.2 to 0.01 degrees per second has also been found to beacceptable. In the latter case, the derivate of the phase angle readingprovides a safety feature for terminating a seal/weld.

As previously described and described throughout the application, theelectrosurgical generator ultimately supplies RF energy to a connectedelectrosurgical tool. The electrosurgical generator ensures that thesupplied RF energy does not exceed specified parameters and detectsfaults or error conditions. In various embodiments, however, anelectrosurgical tool provides the commands or logic used toappropriately apply RF energy for a surgical procedure. Anelectrosurgical tool includes memory having commands and parameters thatdictate the operation of the tool in conjunction with theelectrosurgical generator. For example, in a simple case, the generatorcan supply the RF energy but the connected tool decides how much energyis applied. The generator however does not allow the supply of RF energyto exceed a set threshold even if directed to by the connected toolthereby providing a check or assurance against a faulty tool command.

In one embodiment, each tool comes with an integrated circuit thatprovides tool authentication, configuration, expiration, and logging.Connection of tools into the receptacles or ports initiates a toolverification and identification process. Tool authentication in oneembodiment is provided via a challenge-response scheme and/or a storedsecret key also shared by the controller. Other parameters have hashkeys for integrity checks. Usages are logged to the controller and/or tothe tool integrated circuit. Errors in one embodiment can result inunlogged usage. In one embodiment, the log record is set in binary andinterpreted with offline tools or via the controller.

In one embodiment, connection of a standard bipolar tool into thestandard bipolar outlet will not actively check the tool. However, thecontroller recognizes a connection so that the information on thebipolar outlet can be displayed on the monitor or user interface of theunit. The display reserves a field for the bipolar outlet before theoutlet is activated. In one embodiment, the controller uses timemeasurement components to monitor a tool's expiration. Such componentsutilize polling oscillators or timers, real-time calendar clocks and areconfigured at boot time. Timer interrupts are handled by the controllerand can be used by scripts for timeouts. Logging also utilizes timers orcounters to timestamp logged events.

The tool in one embodiment has memory integrated with or removable fromthe tool. A tool algorithm or script within the tool's memory is loadedinto a script interpreter of the generator. The script provides commandsand parameters readying the tool for use when connected to thegenerator. Upon activation of a switch coupled to the tool, thecontroller detects the switch closure, and authenticates the tool,checks the tool's expiration status, and initializes internal datastructures representing the receptacle's tool. A subsequent activationof the tool switch initiates an event that causes the script to directthe generator to supply RF energy. The controller logs the usage to boththe tool and the generator. When the tool is disconnected from thereceptacle of the generator, the controller resets the informationassociated with the receptacle. The controller constantly monitors thegenerator for proper operation. Unrecoverable errors and faults areannounced and further operation of the system is prevented. All faultsare stored in the controller's memory and/or the tool's memory.

Data from a specific procedure (e.g., from power-up to power-down) isstored on each tool. The tool additionally holds the data from aprocedure, i.e., the number of tool uses, the power setting and faults.Each tool in one embodiment holds the information from all other toolsas well. Tool memory includes but is not limited to the followingparameters: serial number of generator, time stamp, tissue assessmentand endpoint setting for each tool use, cut, coagulation, weld, powersetting, duration of RF and endpoint (auto stop, fault, manual stop,etc.).

The generator logs usage details in an internal log that is downloadable. The generator has memory for storage of code and machineperformance. The generator has reprogrammable memory that containsinstructions for specific tool performance. The memory for exampleretains a serial number and tool use parameters. The generator storesinformation on the type of tools connected. Such information includesbut is not limited to a tool identifier, e.g., a serial number of aconnected tool, along with a time stamp, number of uses or duration ofuse of the connected tool, power setting of each and changes made to thedefault setting. The memory in one embodiment holds data for about twomonths or about 10,000 tool uses and is configured to overwrite itselfas needed.

In one embodiment, the controller includes a state machine interpretermodule that parses tool scripts. Tool scripts represent a tool processfor a specific or given tool. The tool scripts are stored on memoryconnected to or integrated with a tool, the controller or a combinationthereof. The state machine interpreter module responds to specificevents, such as a switch activation/de-activation, tool positions orexceeding measurement thresholds. The module upon response controls theoutput of RF energy and/or electrode activation. In one embodiment, aninterpreter module is provided for each tool input receptacle. Thecontroller detects tool events and forwards the detected event to theappropriate interpreter module. The module in turn requests actions ofthe controller based on the detected event which provides output to theconnected tool associated with the appropriate tool input receptacle andalso the appropriate interpreter module.

In one embodiment, the controller has a specific or predetermined fixedtool script for a specific input receptacle. As such, only this toolscript is used for the tool connected to the particular inputreceptacle. The interpreter module includes an event detector and ascript parser. The event detector receives and identifies tool events,such as a switch activation/de-activation event or a measurement event(e.g., phase threshold exceeded). The event detector formulates requeststo the controller to control RF output, output selection and/orselection of outputs, changes to the display and audio tones. Otherevents detected include detecting hand and foot switches, jaw switches,phase over and phase under-after-over events, shorts and opens, toolscript states. The script parser interprets the tool scripts. Keywordsin the scripts assist the script parser to extract operational commandsand data for tool operation based on a detected event identified by theevent detector. In addition to the voltage, current, etc. set points, atool script specifies the RF source as from the CUT or the COAG source.The script also specifies which electrodes get connected to RF+, RF−, orallowed to float. Because the script controls the electrodeconfiguration, and can set thresholds that trigger events, a script cancompletely reconfigure tool during its use.

The script controls the voltage and current output settings as well assequences of voltage and current settings. For example the permittivityand conductivity of blood vessels is the same independent of size. Asmall blood vessel will fuse very rapidly while a large vessel may takeseveral seconds. Applying a large amount of current to a small vesselmay cause excess tissue damage, while using a small amount of currentwill take an unacceptably long time to perform the fusion function. Soto modify tool performance the script can initially command a smallamount of RF current, and if fusion endpoint is not reached in less thanone second, a high current is commanded to speed the fusion of a largevessel. Another script usage to modify tool performance to switch fromone operation (coagulation) to another operation (cut) is to reconfigurethe tool electrodes and ESG output to simplify a multistep process suchas fuse and cut. When the clinician starts the process the script willfirst setup the unit for the fusion, measure the tissue phase angle thatindicates the fusion endpoint. RF power is then turned on until thefusion endpoint is reached. The unit will then turn off RF power andbeep to indicate that fusion is complete. The unit then switches theelectrodes to the cut configuration, sets the RF output for cut, andrestarts the RF output. The cut operation is stopped by the clinicianwhen the cut is completed.

Referring to FIG. 40, an overview of tool operations is provided. A toolconnected to the electrosurgical generator is verified 601. The endpointis determined 602. The tool applies energy 603, e.g., RF energy, andcontinues until an endpoint is reached or an error condition isdetected. Upon determination of an endpoint being reached or exceeded604, the tool is deactivated (e.g., application of energy is stopped)ending the process.

Based on the tool algorithm for the connected tool, the toolverification and determination of an end point can vary. In particular,a tool short is determined by measuring resistance at a tissuecontacting surface of the tool. If the resistance is less than ten (10)Ohms, a tool short condition is recognized. In accordance with variousembodiments, the product of measured tissue permittivity andconductivity or an initial phase shift is utilized to determine the endpoint for a connected tool.

In accordance with various embodiments, phase shift and/or a phase rateof change is measured throughout the process to determine if an endpointis reached or exceeded. Also, timeout parameters, e.g., a timer orcounter reaching or exceeding a set time limit, or a fault conditionstops or interrupts the process even if the determined end point is notreached or exceeded.

Handheld Electrosurgical Tools

As described generally above and described in further detail below,various handheld electrosurgical tools can be used in theelectrosurgical systems described herein. For example, electrosurgicalgraspers, scissors, tweezers, probes, needles, and other instrumentsincorporating one, some, or all of the aspects discussed herein canprovide various advantages in an electrosurgical system. Variousembodiments electrosurgical tool are discussed below. It is contemplatedthat one, some, or all of the features discussed generally below can beincluded in any of the embodiment of tool discussed below. For example,it can be desirable that each of the tools described below include amemory for interaction with a feedback circuit as described above.However, in other embodiments, the tools described below can beconfigured to interact with a standard bipolar power source withoutinteraction of a tool memory. Furthermore, although it is contemplatedthat certain aspects of these embodiments can be combined with certainaspects of other electrosurgical tools within the scope of thisapplication. Certain aspects of these electrosurgical tools arediscussed generally herein, and in more detail with respect to variousembodiments below.

As discussed above with respect to FIGS. 1A and 1B, and electrosurgicaltool can desirably include a memory. The memory can include anencryption module and a configuration device module. The configurationdevice module can store certain types of tool data. For example theconfiguration device module can store operational parameters for thetool, including software to be transferred to an electrosurgical unitupon successful electrical connection to the electrosurgical unit. Theseoperational parameters can include data regarding variouselectrosurgical procedures to be performed by the tool and correspondingenergy level ranges and durations for these operations, data regardingelectrode configuration of a tool, and data regarding switching betweenelectrodes to perform different electrosurgical procedures with thetool. Advantageously, unlike prior art electrosurgical systems, changesto tool profiles and periodic tool updates can be rapidly made withoutdowntime to electrosurgical generators, as the software for tooloperation can reside in electrosurgical tool itself, rather than thegenerator. Accordingly, updates can be made during tool production.

The configuration device module can further store a data log comprising,for example, a record of information of each previous tool use. Forexample, in some embodiments, the data log can contain timestamp dataincluding an electrosurgical unit identifier, a log of electrosurgicalprocedures perform by the tool, and a log of durations and energiesapplied to the tool. In some embodiments, it can be desirable that useof a particular tool is limited to a maximum usage period or number ofprocedures, especially where electrosurgical tool has not beenconfigured for sterilization and reuse. Accordingly, in someembodiments, the configuration device module can be configured toprevent operation of a tool after a predetermined usage or number ofprocedures. In some embodiments, a tool can comprise a mechanicallockout in addition to or in place of the data log, such as a breakawaysingle-use connector to reduce the possibility of unintended reuse.

In some embodiments, it is desirable that the tool communicate with theelectrosurgical unit through an encrypted protocol. Accordingly, thememory can further store an encryption module, or encryption key tofacilitate this encrypted communication.

As discussed above with respect to FIG. 18 and one be, it can bedesirable that an electrosurgical tool for use in the electrosurgicalsystem includes one or more audio and/or visual indicators. In someembodiments, the electrosurgical tool can include an array of LEDs, or amulti-color LED assembly such as a three-color LED assembly capable ofgenerating many combined colors. The visual indicator can be configuredto illuminate with a color corresponding to the type of electrosurgicalprocedure performed by the tool. Were a tool is configured to performmultiple different types of electrosurgical procedures, desirably thevisual indicator updates to reflect the currently-selectedelectrosurgical procedure. Thus, advantageously, a user can tell, whilewatching the surgical field, what type of electrosurgical procedure thetool is configured to perform.

Electrosurgical Fusion Tool

With reference to FIGS. 41A-41B, one embodiment of a hand heldlaparoscopic sealer/divider or fusion tool 1100 is provided. In theillustrated embodiment, the sealer/divider comprises a handle assembly1110, an elongate shaft 1120 extending from the handle assembly 1110,and a jaw assembly 1130 positioned on the elongate shaft 1120 oppositethe handle assembly 1110. The elongate shaft 1120 has a proximal end anda distal end defining a central longitudinal axis therebetween. In theillustrated embodiment, the handle assembly 1110 comprises a pistol-griplike handle. The elongate shaft 1120 and the jaw assembly 1130, in oneembodiment, are sized and shaped to fit through a 5 mm diameter trocarcannula or access port. In other embodiments, the elongate shaft and jawassembly can be sized and configured to fit through trocar cannulae oraccess ports having other standard, or non-standard sizes. In FIG. 41A,the handle assembly 1110 is shown in a first or initial position inwhich the jaws are open.

With reference to FIGS. 41A-42B, the handle assembly 1110 comprises astationary handle 1112 and an actuation handle 1114 movably coupled tothe stationary handle. In the illustrated embodiment, the stationaryhandle 1112 comprises a housing formed of right 1112R and left handle1112L frames. In other embodiments, the stationary handle 1112 can be asingle component, or can be a housing formed of more than two pieces. Inthe illustrated embodiment, the actuation handle 1114 is slidably andpivotally coupled to the stationary housing, as discussed in furtherdetail below. In operation, the actuation handle 1114 can be manipulatedby a user, e.g., a surgeon to actuate the jaw assembly, for example,selectively opening and closing the jaws.

With continued reference to FIGS. 42A-42B, in the illustratedembodiment, the actuation handle 1114 is coupled to the stationaryhandle 1112 to form a force regulation mechanism 1200 coupling thehandle assembly 1110 to the jaw assembly 1130. Desirably, the forceregulation mechanism 1200 can be configured such that in a closedconfiguration, the jaw assembly 1130 delivers a gripping force betweenthe first jaw 1132 and the second jaw 1134 between a predeterminedminimum force and a predetermined maximum force.

With continued reference to FIGS. 42A-42B, in the illustratedembodiment, the actuation handle 1114 is coupled to the stationaryhandle 1112 at two sliding pivot locations 1202, 1204 to form the forceregulation mechanism 1200. The actuation handle 1114 has a first end1116 including a gripping surface formed thereon, and a second end 1118opposite the first end 1116. In the illustrated embodiment, theactuation handle 1114 is coupled to a pin 1206 adjacent the second end1118. In some embodiments, the actuation handle 1114 can be integrallyformed with a protrusion extending therefrom defining a pin surface,while in other embodiments, a pin can be press-fit into an aperture inthe actuation handle. The 1206 pin can be contained within slots in thestationary handle 1112, such as corresponding slots formed in the rightand left handle frames 1112R, 1112L of the stationary handle housing.These slots can allow the sliding pin 1206 to move over a predeterminedrange. In some embodiments, the slots can be configured to define adesired actuation handle path as the actuation handle is moved from thefirst position corresponding to open jaws to a second positioncorresponding to closed jaws. For example, the illustrated embodimentincludes generally linear slots formed in the stationary handle 1112 atan angle from the central longitudinal axis of the elongate shaft 1120.In other embodiments, the slots can be formed generally parallel to thecentral longitudinal axis. In some embodiments, the slots can becurvilinear.

In the illustrated embodiment, the force regulation mechanism 1200includes a biasing member such as a trigger spring 1208 that biases thepin in a proximal direction towards the rear of the pin slots in theright and left handle frames (see, for example, FIG. 42B). The triggerspring 1208 and the actuation handle 1114 can pivot freely or unhinderedat their attachment point 1202. The biasing member 1208 can be preloadedto a predetermined force. In operation, as a predetermined force isexerted on the actuation handle 1114, a biasing force exerted by thetrigger spring 1208 is overcome, and the second end 1118 of theactuation handle 1114 can translate generally distally, guided by thepin in the slots.

While the illustrated embodiment includes a pin-in-slot arrangementcoupling one pivot point of the actuation handle to the stationaryhandle, in other embodiments, it is contemplated that other connectionscan be formed. For example, in some embodiments, a slot can be formed inthe actuation handle and a mating projection can be formed in thestationary handle. Furthermore, while the illustrated embodimentincludes a tension coil spring forming the biasing member, in otherembodiments, other biasing members are contemplated. For example, thebiasing member can comprise a compression spring, a torsion spring, anelastomeric band, a fluid-filled shock absorbing unit, or anothersuitable biasing device.

With continued reference to FIGS. 42A-42B, in the illustratedembodiment, the actuation handle 1114 is slidably and pivotably coupledto the stationary handle 1112 at a location between the first and secondends 1116, 1118 of the actuation handle. An actuation member such as apull block 1250 can be coupled to the actuation handle. In theillustrated embodiment, an actuation path of the pull block 1250 isdefined by rails formed in the right and left handle frames 1112L,1112R. When the actuation handle 1114 is moved proximally, the pullblock 1250 also moves, effectively closing the jaws thereby clamping anytissue between the jaws. In the illustrated embodiment, the rails guidethe pull block 1250 to slide proximally and distally while limitingmovement in other directions. In other embodiments, various other guidemembers such as a pin-in-slot arrangement can define the actuation pathof the actuation member.

As illustrated, the pull block 1250 comprises a generally rectangularprismatic structure having a generally open top and bottom faces and asubstantially closed proximal end. The actuation handle 1114 can extendthrough the top and bottom faces of the pull block 1250. An edge of theactuation handle 1114 can bear on the proximal end of the pull block1250 such that movement of the actuation handle 1114 relative to thestationary handle can move the pull block 1250 generally longitudinallyalong the actuation path defined by the rails. A distal end of the pullblock 1250 can be coupled with an actuation shaft such as an actuationtube, bar, or rod, which can extend longitudinally along the elongateshaft of the sealer/divider. Thus, in operation, movement of theactuation handle 1114 from the first position to the second positiontranslates the pull block 1250 longitudinally within the stationaryhousing, which correspondingly translates the actuation rod generallylinearly along the longitudinal axis with respect to the elongate shaft.Movement of this actuation tube can control relative movement of thejaws in the jaw assembly.

With continued reference to FIGS. 42A and 42B, in some embodiments, thesealer/divider can include a latch mechanism 1260 to maintain theactuation handle 1114 in the second position with respect to thestationary handle. In the illustrated embodiment, the actuation triggercomprises an extended latch arm 1262 which can engage a matching latch1264 contained within actuation handle 1112 for holding the actuationtrigger at a second or closed position. In other embodiments, it iscontemplated that the one portion of the latch mechanism can be formedon a portion of the actuation handle 1114 adjacent the second end of theactuation handle 1114, and a mating portion of the latch mechanism canbe formed on the actuation handle 1112. In still other embodiments, itis contemplated that the a portion of the latch mechanism can be formedon the pull block 1250 and a mating portion of the latch mechanism canbe formed on the stationary housing.

In some embodiments, the jaw assembly 1130 of the sealer/dividercomprises an advanceable cutting blade 1400 (FIG. 44B) that can becoupled to a blade actuator such as a blade trigger 1402 positioned onthe handle assembly 1110. A blade actuation mechanism 1404 canoperatively couple the blade trigger to the cutting blade. In theillustrated embodiment, the blade trigger 1402 is positioned on aproximal surface of the handle assembly such that it can be easilyoperated in a pistol-grip fashion. As illustrated, the blade actuationmechanism 1404 comprises a pivoting blade advancement link thattransfers and reverses the proximal motion of the blade trigger 1402 toa blade actuation shaft assembly coupled to the cutting blade. In otherembodiments, the blade trigger 1402 can be positioned elsewhere on theactuation handle 1112 such as on a distal surface of the actuationhandle 1112 such that distal movement of the blade trigger 1402 canadvance the cutting blade distally without transfer of advancementdirections via a linkage. In operation, a user can move the bladetrigger 1402 proximally to advance the cutting blade 1400 from aretracted position to an extended position. The blade actuationmechanism 1404 can include a biasing member such as a blade returnspring 1406 to biases the blade advancement lever distally within theactuator and thereby bias the cutting blade 1400 into the retractedposition.

With reference to FIG. 42C, the handle assembly also comprises a wireharness 1500. The wire harness 1500, in certain embodiments, comprisessix insulated individual electrical wires or leads contained within asingle sheath. As illustrated, the wire harness 1500 can exit thehousing of the actuation handle 1112 at a lower surface thereof and canrun generally upwards along the interior of the actuation handle 1112.In other embodiments, other wire routings can be made. For example, insome embodiments, the wire harness 1500 can exit a lower portion of theproximal surface of the actuation handle 1112. The wires within theharness can provide electrical communication between the sealer/dividerand an electrosurgical generator and/or accessories thereof, asdiscussed above.

In certain embodiments of sealer/divider, inside the actuation handle1112, two of the leads are attached to rotational coupling clips 1502configured to allow infinite rotation of the jaw assembly 1130, asdiscussed in greater detail below, two of the other leads are attachedto a visible indicator 1504, such as a multi-colored LED, and theremaining two leads are attached to a switch 1506. In some embodiments,the switch 1506 is connected to a user manipulated activation button andis activated when the activation button is depressed. In one aspect,once activated, the switch 1506 completes a circuit by electricallycoupling the two leads together. As such, an electrical path is thenestablished from an electrosurgical generator to the actuator to supplyradio frequency power to one of the two leads attached to the rotationalcoupling clips 1502.

Referring now to FIG. 43, the handle assembly is coupled to a rotationalshaft assembly 1600. In certain embodiments, coupling of the handleassembly to the rotational shaft assembly 1600 is configured to allowinfinite 360 degree rotation of the jaw assembly 1130 with respect tothe handle assembly. In the illustrated embodiment, the handle assembly1110 connects to the shaft 1120 at five locations or connectionsproviding a continuous 360 degree rotation of the entire shaft whilesimultaneously allowing complete actuation of the actuation handle 1114,e.g., sealing and/or dividing of the vessel. As illustrated, the firsttwo connections are rotational coupling clips 1502 which make contactwith the rotational shaft assembly at the actuation tube and conductivesleeve. The next area of engagement or the third connection is arotational hub assembly 1602 which is located between the two rotationalcoupling clips 1502.

With continued reference to FIG. 43, the rotational shaft assembly 1600is desirably contained within the right and left handle frames such thatproximal and distal movement of the jaw assembly 1130 with respect tothe handle assembly 1110 is prevented while allowing for rotationalmovement. For example, inwardly-extending flanges can be formed on theactuation handle 1112 that interfere with proximal and distal movementof the rotational hub assembly 1602, rotational coupling clips 1502, orother components of the rotational shaft assembly 1600. The fourthconnection is at a plurality of threaded nuts 1604 and the pull block1250. The fifth connection is between the blade lever 1608 and a rearblade shaft 1606. The rotation shaft assembly 1600 can also comprises arotation knob 1610 which is fixed to the outer cover tube. The rotationknob 1610 allows the surgeon to rotate the shaft of the device whilegripping the handle. While the rotational shaft assembly 1600 isillustrated as having five connection locations with the actuationhandle 1112, in some embodiments, a rotational shaft assembly can havefewer connection locations, such as for example, 1, 2, 3, or 4connection locations. In still other embodiments, it can be desirablethat a rotational shaft assembly has more than 5 connection locations,such as, for example 6, 7, 8, or more than 8 connection locations.

Desirably, the rotational shaft assembly 1600 provides the vesselsealer/divider with continuous 360 degree rotation throughout operationof the electrosurgical instrument. By using rotational coupling clips1502 for the electrical connections to the shaft, the shaft can operate,e.g., deliver RF energy, at any orientation or rotation of the jawassembly 1130 relative to the handle assembly. Thus, advantageously, thesurgeon is provided more surgical options for the placement andactivation of the sealer/divider. Advantageously, with a rotationalshaft assembly 1600, the wires and electrical and mechanicalconnections, as such, do not interfere with continuous, infiniterotation of the shaft. To maintain a bipolar connection through therotational shaft assembly 1600, one of the electrical connections iselectrically isolated from other conductive portions of the shaft.

As discussed in further detail below, in some embodiments, thesealer/divider can be configured to grasp with a gripping force within apredetermined range. In one embodiment, an overall tolerance stack-upover the length of the shaft can be controlled so that the force appliedto the jaw assembly 1130 from the handle assembly can be maintainedaccurately within the predetermined range. The overall length of theshaft 1120 can be controlled by using threaded nuts 1604 and a threadedcoupling. The threaded nuts 1604 can be adjusted to tightly control thelength of the elongate shaft 1120. The length is controlled bymaintaining the location of the threaded nuts 1604 in relation to thehub portions of the shaft. In the illustrated embodiment, attached tothe distal end of the actuation tube is a threaded coupling. Attached tothe threaded coupling are two threaded nuts, which are configured toengage with the pull block 1250. The pull block 1250 engages with thethreaded nuts 1604 which are attached to the rear of the actuation tube,causing the actuation tube to move proximally. The described interactioncan also be reversed so that the threaded nuts 1604 and coupling areattached to an outer cover tube rather than the actuation tube. In otherembodiments, other length adjustment mechanisms can be used to controlthe overall tolerance stack-up such as a lock screw to selectivelysecure the position of the pull block 1250 at a desired locationrelative to the actuation tube or toothed ratchet interfaces definingset distance relationships between the pull bock and the actuation tube.In other embodiments, a length adjustment mechanism can be positioned atthe distal end of the elongate shaft, e.g., where the elongate shaftinterfaces with the jaw assembly 1130.

Referring to FIGS. 44A-44D, the elongate shaft 1120 can comprise aplurality of actuation members extending therethrough. In theillustrated embodiment, the elongate shaft comprises an actuation tube1122 coupling the jaw assembly 1130 with the handle assembly 1110 and ablade actuation shaft assembly 1124 coupling the blade trigger 1402 withthe cutting blade. In some embodiments, the blade actuation shaftassembly 1124 comprises a two-piece shaft having a proximal portion anda distal portion. The proximal portion of the blade shaft assembly canterminate at a proximal end at an interface node 1126. In theillustrated embodiment, the interface node 1126 comprises a generallyspherical protrusion portion which is adapted to engage the bladeadvancing lever. In other embodiments, the interface node can compriseother geometries such as cubic or rectangular prismatic protrusions. Inthe illustrated embodiment, the proximal portion of the blade shaft isoperatively coupled to the distal portion of the blade shaft assembly1124. The distal portion of the blade shaft can comprise a mount at itsdistal end for attachment of the cutting blade. In the illustratedembodiment, the mount comprises at least one heat stake post. In certainembodiments, both the proximal and distal portions of the blade shaftare at least partially positioned within a generally tubular section ofthe actuation tube 1122. (see, e.g., FIG. 44C).

As discussed above with respect to length adjustment of the elongateshaft 1120, in the illustrated embodiment attached to the distal end ofthe actuation tube 1122 is a threaded coupling 1150 (FIG. 44D). Asillustrated, attached to the threaded coupling 1150 are two thread nuts1604, which are configured to engage with the pull block 1250. In theillustrated embodiment, the actuation tube 1122 is housed within anouter cover tube. While the actuation tube 1122 is illustrated as agenerally tubular member that can be nested within the outer cover tube1126, and that can have a blade actuation shaft 1124 nested within it,in other embodiments, a non-tubular actuation member can be used, forexample, a shaft, a rigid band, or a link, which, in certain embodimentscan be positioned generally parallel to the blade actuation shaft withinthe outer cover tube.

With continued reference to FIG. 44A, in the illustrated embodiment,attached to the distal end of the outer cover tube 1126 is therotational shaft assembly 1600. The rotational shaft assembly 1600comprises two mating hubs 1602 and a conductive sleeve 1610. In theillustrated embodiment, the hubs 1602 snap together, engaging with theouter cover tube. In other embodiments, the hubs can be of a monolithicconstruction and configured to interface with mating features on theouter cover tube. The conductive sleeve 1610 can be attached to theproximal portion of the assembled hubs after they are attached to theouter cover tube. When the conductive sleeve 1610 is attached to therear of the assembled hubs 1602, the sleeve 1610 traps the exposed endof an isolated wire 1612 (see FIG. 44D). In the illustrated embodiment,the isolated wire 1612 extends from its entrapment point under theconductive sleeve through a slot in the actuation tube 1122 and theninside a protective sleeve 1614. The protective sleeve 1614 and isolatedwire 1612 extend distally inside the actuation tube 1122, towards thejaw assembly 1130. In other embodiments, the isolated wire can be formedintegrally with a protective sheath and no separate protective sleeve ispresent in the actuation tube.

With reference to FIGS. 45A-45C, attached to the distal end of theelongate shaft 1120 is the jaw assembly 1130. In certain embodiments,the jaw assembly 1130 comprises a lower jaw 1134, upper jaw 1132, upperconductive assembly 1142, lower nonconductive spacer 1144, and jaw pivotpin 1146. In the illustrated embodiments, the jaw pivot pin 1146pivotally couples the upper and lower jaws 1132, 1134 and allows theupper jaw 1132 to pivot relative to the lower jaw 1134. In otherembodiments, other pivotal couplings are contemplated. As illustrated,the proximal portion of the upper jaw 1132 extends through the lower jaw1134 and into a hole in the actuation tube 1122.

In some embodiments, one jaw can be fixed with respect to the elongateshaft 1120 such that the opposing jaw pivots with respect to the fixedjaw between an open and a closed position. For example, in theillustrated embodiment, the proximal portion of the lower jaw 1134extends inside the cover tube 1126 and is crimped in place, fixing thejaw assembly 1130 to the rotation shaft assembly 1600. Thus, in theillustrated embodiment, the upper jaw 1132 is moveable with respect to afixed lower jaw 1134. In other embodiments, both jaws can be pivotallycoupled to the elongate shaft such that both jaws can pivot with respectto each other.

Attached to the upper jaw 1132 is the upper conductive assembly 1142,which comprises a nonconductive portion 1702 and a conductive pad 1704(see FIG. 45B). The nonconductive portion 1702 isolates the conductivepad 1704 from the upper jaw 1132, likewise isolating it from the rest ofthe shaft assembly 1120. The isolated wire 1612 can be routed toelectrically couple the conductive pad 1704 on the upper jaw 1132 to thewiring harness 1500 in the handle assembly 1110. In the illustratedembodiment, the isolated wire 1612 extends from the distal end of theprotective sleeve which is housed at the proximal end of the lower jawand extends into the upper jaw 1132. The upper jaw 1132 can have a slotpositioned to receive the isolated wire. The isolated wire 1612 thenextends through a hole in the upper jaw 1132 and drops into a slot inthe nonconductive portion. The isolated wire then extends to the distalend of the nonconductive portion and drops through to the conductive pad(see FIG. 44D).

The jaw assembly 1130 can include one or more nonconductive spacemaintaining members such as spacers 1144 to reduce the risk thatelectrodes on the upper jaw 1132 and lower jaw 1134 can come into directcontact and create a short. In the illustrated embodiment, the lowernonconductive spacer 1144 is housed inside the u-groove portion of thelower jaw and contains space maintaining protrusions which prevent theconductive pad from contacting the lower jaw (see FIG. 45C).

Turning now to some of the operational aspects of the electrosurgicalinstruments described herein, once a vessel 1030 or tissue bundle hasbeen identified for sealing, the upper and lower jaws are placed aroundthe tissue (see FIG. 46A). The actuation handle 1114 is squeezed movingthe actuation handle 1114 proximally with respect to the actuationhandle 1112 (see FIG. 46B). As the actuation handle 1114 movesproximally it pushes the pull block 1250 along the rails in the rightand left handle frames. The pull block 1250 engages with the threadednuts 1604 which are attached to the rear of the actuation tube 1122,causing the actuation tube 1122 to move proximally. Proximal movement ofthe actuation tube pivots the upper jaw 1132, coupled to the pull tube,towards the lower jaw, effectively clamping the tissue (see FIG. 46C).The force applied to the tissue by the upper jaw is translated throughthe pull tube and pull block 1250 to the actuation handle 1114. Once thepreloaded force has been overcome, the actuation handle 1114 will beginto move the sliding pin 1206 distally (see FIG. 46D). When the preloadon the trigger spring has been overcome, the actuation handle 1114 pivotpoint shifts from the sliding pin 1206 to the rear portion of the pullblock 1250 where it contacts the actuation trigger. The sliding pin 1206can advance distally because the preloaded force on the trigger spring1208 has been overcome.

The continued manipulation of the actuation handle 1114 pivots theactuation handle 1114 to a location where the actuation handle 1114engages with the latch mechanism 1260 in the right and left handleframes that maintains the trigger in the engaged position and preventsthe trigger from returning to an opened position. When the engagedposition is reached and nothing is present between the upper and lowerjaws 1132, 1134, the trigger spring is extended to a distance thatensures that the force applied to the electrodes of the Jaw assembly1130 is near the lower end of the force range required for optimalvessel sealing. When a large, e.g., maximum, amount of tissue is placedin the jaws, the actuation handle 1114 extends the trigger spring 1208 agreater distance. However, the trigger spring 1208 ensures that themaximum amount of force applied does not exceed the maximum end of theforce range used for optimal vessel sealing. From the engaged position,sealing radio frequency energy is applied to the tissue by depressingthe power activation button. Once the tissue has been sealed, theactuation trigger can be reopened by continuing proximal advancement toa position that allows the actuation trigger's finger portion todisengage from the latch portions of the left and right handle frames.(See FIGS. 46A-46F))

The floating dual pivoting mechanism including a sliding pin 1206 and apull block 1250 described above desirably provides a minimum force,optimal for sealing vessels and tissue, is maintained regardless of theamount of substance contained between the upper and lower jaws. Thismechanism also reduces the risk that an extremely large amount of forceis applied to the tissue. If too much force is applied to a vessel ortissue bundle, potential damage could occur. Thus, if a very smallvessel or thin tissue bundle is clamped within the jaw, the instrumentapplies the minimum amount of force required to obtain a good tissueweld. The same is true with a very large vessel or tissue bundle. Sincethe travel of the jaw can vary greatly depending on tissue thickness,the force applied by the jaw is adjustable. It is desired that theinstrument be self-adjusting and automatic (no action from the user).The floating dual pivot mechanism described below provides theself-adjustment, applying a specific range of force along the length ofthe electrode.

Once the actuation handle 1114 has been depressed to a predeterminedforce range for optimal vessel sealing, it will engage the matchinglatch of the right and left handle frames, locking the actuation triggerfrom moving further distally (See FIG. 46E). At this point the user candepress the activation button, applying the appropriate energy to thetissue for proper sealing.

Once the tissue has been sealed, the user can actuate the blade trigger1402. When the blade trigger 1402 is moved proximally, the blade leverpivots, forcing the front and rear blade shafts and cutting blade 1400to move distally. The cutting blade advances forward and divides thesealed portion of the tissue (see FIG. 46F). When the user releases theblade trigger 1402, the blade spring resets the cutting blade to itsoriginal position. When the blade trigger 1402 has been returned to itsoriginal or initial position the user can continue to squeeze theactuation handle 1114 to open the upper jaw. Continued proximal movementof the actuation handle 1114 will disengage the actuation handle 1114from the latch mechanism 1260 of the right and left handle frames bybiasing the extended arm portion 1262 of the actuation trigger upwards,over the end of the latch, to a position where the trigger can bereleased (see FIG. 46G).

The electrosurgical instrument is connectable to an electrosurgicalgenerator specifically configured to apply the proper amount of energyto the tissue when the activation button is depressed, such as theelectrosurgical generator described above. With reference to FIG. 47,the instrument is also connectable to an intermediate control unit 1800in conjunction with an electrosurgical generator. The intermediatecontrol unit 1800 can monitor the tissue sealing and ensure that theproper amount of sealing energy is applied to the tissue. The controlunit 1800 in one aspect can have a set of cables configured to plug intomost typical electrosurgical generators. The control unit also has aport for connecting the wiring harness 1500 plug from the instrument(see FIG. 47).

With continued reference to FIG. 47, in certain embodiments, thenon-sterile power controller interfaces with the sterile vesselsealer/divider through a cord extending from the sealer/divider beyondthe sterile field and plugged into the controller. In one aspect, thecontroller regulates and/or distributes power from a non-sterilereusable power supply to which the controller is attached or integrated.In some embodiments, the controller can be configured for a single useto maintain sterility of the surgical environment. In order to preventreuse of the non-reusable controller, the cord of the electrosurgicaltool, once plugged into the non-sterile controller cannot be removed.This connection permanently couples the sterile and non-sterileportions, preventing the user from being able to disconnect thecontroller for reuse in unintended surgical procedures or purposes. (seeFIG. 47)

In grasping jaw assemblies such as the jaw assembly 1130 of theelectrosurgical tool, the gripping force generated between the jaws canvary along the length of the jaws from a relative maximum Fmax near theproximal end to a relative minimum Fmin near the distal end. In someembodiments, the electrosurgical tool can be configured such that theforces are optimized along the length of the active electrode portionsof the jaws, a predetermined force range for vessel sealing ismaintained. A predetermined maximum amount of force utilized to obtain aproper vessel seal is desirably not exceeded at the proximal end of theactive electrodes (closest to the pivot). In addition a gripping forceat the distal most ends of the active electrodes is desirably greaterthan a predetermined minimum amount of force for optimal vessel sealing.Desirably, the gripping force generated at every point along the jawassembly 1130 is within the range defined by the predetermined maximumforce and the predetermined minimum force to achieve optimal sealing.(See FIG. 48A).

In some embodiments, the electrode width to form vessel seals is betweenabout 0.25 mm and about 1.5 mm. In other embodiments, the electrodewidth is desirably between about 0.4 mm and about 1 mm. In otherembodiments, the electrode width is preferably between about 0.6 mm and0.8 mm. In some embodiments, the electrode width is approximately 0.75mm. With an electrode of 0.75 mm, and the sufficient pressure for thistype of electrode to achieve a vessel seal is approximately 3 pounds(see FIGS. 48B and 48C). However it can bee seen from FIG. 48C that aforce range of approximately 0.4 pound to 2.3 kg on a 0.75 mm electrodecan maintain burst pressures greater than 15 psi. In some embodiments,the jaw and electrode arrangement desirably can maintain a pressure ofbetween 3 and 39 kg/cm̂2, more desirably 10-30 kg cm̂2, and preferablyapproximately 23 kg/cm̂2. Embodiments having different electrode widthscan have different force ranges. In order to maximize sealing surfacearea while still maintaining the electrode configuration describedabove, in some embodiments, multiple rows of 0.75 mm electrodes may beprovided (see FIG. 48D).

In some embodiments, electrode geometry on the conductive pads of thejaw assembly 1130 ensures that the sealing area completely encloses thedistal portion of the blade cutting path. Single linear electrodes couldcause vessel leakage when only a portion of a vessel is sealed. In oneembodiment, the electrodes positioned on the jaw assembly 1130 comprisea single u-shaped electrode 1902 surface on each of the upper and lowerjaws. Each u-shaped electrode can comprise generally parallel linearlegs 1910 extending from a proximal end of the conductive pad of the jawtowards the distal end and a curved connector 1912 at the distal endextending from one leg to the opposite leg. Desirably, the u-shapedelectrodes can completely encompass the distal end of the blade cuttingpath. In other embodiments, to provide a greater sealing area, two ormore spaced u-shaped electrode surfaces on both the upper and lower jawscan be provided (see FIG. 49). In some embodiments, the electrodes 1904can be connected at the distal ends to create a completely enclosed seal(see FIG. 49). In certain embodiments one or multiple bridge members1908 between the u-shaped electrode 1906 surfaces can further ensurethat the sealing area completely encloses the distal portion of theblade cutting path.

In some embodiments, for some surgical procedures the outer shape of thejaws 1130′ can be curved such that the distal ends of the jaws areoffset with respect to the longitudinal axis from the proximal ends ofthe jaws to improve visibility for a user such as a surgeon. Inembodiments with curved jaws, the u-shaped electrodes can also beprovided in a curved fashion while still maintaining proper electrodewidth and spacing (see FIG. 50).

With reference to FIG. 51, in certain embodiments, the electrosurgicaldevice can include a tissue dissector formed on the jaw assembly 1130″.Advantageously, this integrated tissue dissector can facilitatedissection of non-vascular tissue either bluntly or electro-surgically,without having to exchange the vessel sealer/divider with anotherinstrument. Thus, this multiple tool functionality can advantageouslyfacilitate quicker surgical procedures. The reduced number of toolexchanges can be especially advantageous in laparoscopic procedures orprocedures with relatively limited access as tool exchanges can be timeconsuming in these surgical environments.

With continued reference to FIG. 51, in some embodiments, one of thejaws of the jaw assembly 1130″ can have an extended distal end distallybeyond the distal end of the other jaw (see FIG. 51). In the illustratedembodiment, the lower jaw 1134″ can have an extended distal end.Advantageously, in embodiments where the lower jaw 1134″ is pivotallyfixed to the elongate shaft, this extended arrangement can facilitatestability of the lower jaw during dissection. In other embodiments, theupper jaw 1132 can have an extended distal end, allowing the tissuedissector to be pivoted during the dissection operation by movement ofthe actuation handle 1114. In some embodiments, the extended distal endcan be tapered in shape such that the distal end is relatively short andnarrow compared to relatively more proximal portions of the jaw.Advantageously, this tapered shape allows the distal end to accesstissue positioned in relatively confined environments while reducing therisk that adjacent tissue is contacted.

With reference to FIGS. 52A, 52B, In some embodiments, both jaws of thejaw assembly 1130′″ are tapered laterally and/or in height along thelength of the jaw's electrode portions, or at least part of theelectrode portions. In these embodiments, the jaw assembly 1130′″ has alow-profile distal end which can be used for tissue dissection.Advantageously, the low-profile distal end can also enhance access ofthe jaw assembly 1130′″ to relatively confined surgical environments.

With reference to FIGS. 53A, 53B, in certain embodiments, acutting/coagulating electrode can be disposed on an exterior surface ofthe jaw assembly 1130 to provide tissue dissection. In some embodiments,the cut/coagulation electrode is located on the jaw at, for example, thedistal end on the outer surface of either the upper or lower jaw (seeFIG. 53A). Desirably, the electrode 1920 can be electrically isolated orinsulated from other components of the jaw assembly 1130, providing anactive electrode for the bi-polar instrument. As such, an isolated wirecan extend from the cut/coagulation electrode 1920 to the proximal endof the elongate shaft 1120 (similar to the isolated wire extending fromthe conductive pad on the upper jaw) to electrically couple thecut/coagulation electrode to the wiring harness 1500 of theelectrosurgical tool in the handle assembly. In some embodiments, theisolated wire can extend within a protective sleeve within the outercover tube of the elongate shaft. In other embodiments, the isolatedwire can be integrally formed with a protective sheath. The isolatedwire also in one aspect is coupled to a rotational connection, e.g., arotational clip, similar to the isolated wire extending for theconductive pad.

With reference to FIG. 53B, the cut/coagulation electrode in one aspectcan be selectively activated by at least one actuation button 1922, 1924or switch on the handle assembly 1110. In some embodiments, the handleassembly can comprise a cut button 1922 to actuate the electrode with atissue cutting electrosurgical signal and a coagulation button 1924 toactuate the electrode with a tissue coagulating electrosurgical signal.For example, in FIG. 53B, separate cut and coagulation buttons areillustrated on the actuator adjacent a tissue sealing button to actuatethe electrodes on inner surfaces of the jaws. In other embodiments, asingle, multifunction switch or button can actuate the cut/coagulationelectrode in the desired configuration. In still other embodiments, thecut/coagulation electrode can be configured to receive only a cutting oronly a coagulation electrosurgical signal, and a single correspondingactuation button or switch can be used to selectively actuate theelectrode.

The vessel sealer/divider can use thin metallic tubes and small diametermachined rods for the internal elongated components used to actuate jawssuch as the actuation tube and the blade actuation shaft. However, suchcomponents can be costly and in some embodiments, manufacturing andmaterials costs can be desirably reduced through the use of elongateinjection molded plastic components. As discussed above with respect tothe blade actuation shaft 1124, in some embodiments, costs andmanufacturing difficulties can be reduced further through the use of anelongated shaft formed of two mating polymer shaft sections 124 a, 1124b such as a proximal or rear shaft portion and a distal or front shaftportion. In some embodiments, the two shaft portions 1124 a, 1124 b canbe connected by interlocks 1960, e.g., projections on one shaft sectionor component mating with corresponding slots on the other shaft section,to maintain concentricity and prevent unnecessary movement in theiraxial direction (see FIG. 54A-C). In other embodiments, other matingstructures can be formed on the two mating shaft portions. For example,one of the shaft portions can be formed with one or more barbs thereonand the other shaft portion can be formed with a recess configured toreceive and retain the barbs. In still other embodiments, the two matingshaft portions can be adhered with a chemical adhesive or epoxy, eitherin addition to, or in place of interlocks formed on the shaft portions.

With reference to FIGS. 55A and 55B, in certain embodiments, theelongate shaft 1120 of the electrosurgical tool can be configured suchthat the outer surface thereof does not translate proximally anddistally during actuation of the jaw assembly 1130 by the actuationhandle 1114. In other embodiments, moving the outer shaft component canbe used to open and close the jaws and provide a proper clamping forcewithout manipulating the handle assembly. However, moving the outershaft component can also cause the vessel sealer/divider to move inrelation to a trocar seal and thus potentially complicating a gas sealbetween the sealer/divider and the insufflated body cavity. As such, itcan be desirable that the outer most shaft components remainingstationary throughout a surgical procedure. As such, in certainembodiments, the elongate shaft maintains the moving components (e.g.,the pull tube and the blade actuation shaft) on the inside of astationary outer cover tube (which may also con a dielectric coating orinsulating sleeve). With continued reference to FIGS. 55A and 55B, asillustrated, the stationary outer cover tube is connected to thestationary portion of the jaws, while the pull tube is connected to themoving portion of the jaws (e.g., the upper jaw). Thus, as the jawassembly 1130 is actuated from an open position (FIG. 55A) to a closedposition (FIG. 55B), the pull tube translates longitudinally proximallywhile the outer cover sleeve remains stationary.

As discussed above with respect to the electrosurgical system, incertain embodiments the electrosurgical tool can comprise a memory suchas a tool ID chip mounted on a small PCB. In some embodiments, the PCBcan be disposed on or in the actuation handle 1112. In otherembodiments, the PCB and chip can be integrated in the plug of thewiring harness. The PCB and chip can be molded with a tool-specificpattern. The tool ID chip and PCB can be electrically connected into thewiring harness and plug of the electrosurgical tool. A “spacer” betweenthe plug and the tool ID chip, can allow the use of the same connectorfor all tools. In some embodiments, the spacer can have the same shapefor all tools on the plug side, and a tool-specific pattern on the chipside such that during assembly there is a reduced risk that a PCB forone type of electrosurgical tool can be assembled into a different typeof electrosurgical tool.

As discussed above with respect to the electrosurgical system, when theplug is inserted into the generator, the encrypted tool informationstored in the memory is verified. General information (serial number oftool and generator) are exchanged, and the tool-specific software isuploaded into the generator. With completion of each tool use,tool-specific information (connections to generator, individual tooluses, errors, etc.) can be communicated, if needed, and stored in memoryof the generator, the tool chip or both. In exemplary embodiment, thegenerator's memory is sized to hold data for about two months while thetool chip's memory can hold data for one surgical procedure.

As discussed above with respect to the electrosurgical system, in someembodiments, the electrosurgical fusion tool can be used in a systemwhich monitors various operational parameters and determines aradiofrequency endpoint based on phase angle.

Although the present invention has been described in certain specificaspects, many additional modifications and variations would be apparentto those skilled in the art. It is therefore to be understood that thepresent invention may be practiced otherwise than specificallydescribed, including various changes in the size, shape and materials,without departing from the scope and spirit of the present invention.Thus, embodiments of the present invention should be considered in allrespects as illustrative and not restrictive.

Electrosurgical Dissection Tool

Laparoscopic surgical procedures typically require the dissection ofconnective or vascular tissue. Depending on factors such as tissue type,size, location and condition of the specific tissue, different tools andtechniques can be used to perform a specific procedure. The choice of anindividual tool can be based on functionality combined with a desirethat the selected tool provide relatively little traumatic damage to thesurrounding tissue. As an example, the dissection of connective tissueis usually performed by mechanical or electrosurgical cutting, whereasthe dissection of vascular tissue typically relies on ligatingtechniques employing clips or staplers followed by a mechanical cut.Consequently, a typical laparoscopic procedure including dissection ofboth connective tissue and vascular tissue calls for multiple toolsbeing consecutively exchanged through trocar access ports to thesurgical site. This tool exchange increases both the cost and time ofthe surgical procedure. It is hence desirable to providemulti-functional tools that can greatly reduce the number of toolexchanges during laparoscopic procedures.

Referring now to FIG. 56, in the illustrated embodiment, a bloodlesstissue-dissecting tool 2101 comprises a proximal hand-piece 2102 thatconnects through a shaft 2103 to a distal end-piece 2104. Activation ofthe trigger 2105 on the hand-piece 2102 allows closing and opening ofthe jaw elements 2106, 2107 on the distal end-piece 2104 so that tissuecan be clamped between the upper 2106 and lower 2107 jaw elements.

With continued reference to FIG. 56, in some embodiments, the tool 2101can be configured to be electrically coupled to an electrosurgicalgenerator. For example, in some embodiments, the tool 2101 can includean integrated power cord, or a socket or other connector adapted toreceive a power cord. At least a portion of the tool can be selectivelyenergized through actuation of a control or switch on theelectrosurgical generator. For example, in some embodiments, the toolcan be energized with a handswitch or a footswitch on or coupled to theelectrosurgical generator.

With reference to FIG. 57, an exemplary prior art electrosurgical deviceis illustrated. Electrosurgical tissue sealing devices that include amechanical cutter can be used to first electrosurgically coagulate andthen mechanically cut through a variety of tissue types. Certainharmonic tissue dividers can also be used to coagulate and/or to dissecta variety of tissue, ranging from connective to highly vascular tissue,such as organs.

As schematically depicted in FIG. 57, prior-art electrosurgical tissuedissectors include a lower jaw forming a first electrode 2201 and anupper jaw forming a second electrode 2202. In the prior art devices, thetwo jaw elements—or electrodes 2201, 2202—supply a relatively largeamount of pressure to the tissue. High pressure with simultaneousapplication of electrical energy to the compressed tissue can be used topermanently occlude very large blood vessels by electrosurgical vesselfusion. After the electrical fusion process has been completed, thetissue can be separated by advancing a mechanical blade 2203.

In contrast to the prior art electrosurgical devices, with reference toFIG. 58 a, one embodiment of an electrosurgical tool that can beconfigured in either an electrosurgical coagulation state or anelectrosurgical cutting state is shown. In the illustrated embodiment, alower jaw element 2301 comprises a first coagulating electrode 2302, asecond coagulating electrode 2303, and an electrosurgical cuttingelectrode 2304. Each of the electrodes can be electrically isolated fromeach other by insulating members 2305. The upper jaw 2306 is notenergized in this embodiment, but is merely used to press tissue againstthe lower jaw element 2301.

With the electrode arrangement illustrated in FIG. 58 a, tissue that isin contact with the lower jaw element 2301 can be coagulated byelectrically coupling each of the two coagulation electrodes 2302, 2303with the corresponding outlet of a bipolar electrosurgical unit. Here,the two coagulation electrodes 2302 and 2303 can be supplied withelectrical energy having opposite polarities. In some embodiments, itcan be desirable that the supplied electrical energy has a potentialdifference of no more than 200V to reduce the risk of arcing and thatelectrode 2302 and 2303 have the same contact area with the tissue. Thelatter ensures the same electrosurgical effect for both electrodes.

With continued reference to FIG. 58 a, after the two coagulationelectrodes 2302, 2303 have achieved substantial hemostasis within thecoagulated tissue volume, the tissue can be electrosurgically cut byapplying energy to an electrosurgical cutting electrode 2304. During theelectrosurgical cutting operation, the two coagulation electrodes 2302,2303 can be electrically coupled to a corresponding outlet or outlets ofa bipolar electrosurgical unit to function as return electrodes. Here,the potential difference between the cutting electrode 2304 and the tworeturn electrodes 2302 and 2303 can desirably be between approximately300-500V, while the two return electrodes can desirably be substantiallyequipotential.

With continued reference to FIG. 58 a, in some embodiments, it can bedesirable that the relative contact area of the electrodes with thetissue is much smaller for the cutting electrode 2304 than for thereturn electrodes 2302, 2303. For example, in some embodiments,desirably the cutting electrode can have a contact area that is betweenapproximately 1% and 20% as large as a contact area of one of the returnelectrodes 2302, 2303. More desirably, the cutting electrode can have acontact area that is between about 5% and 10% as large as a contact areaof one of the return electrodes 2302, 2303. In one embodiment, thecutting electrode can have a contact area that is approximately 10% aslarge as a contact area of one of the return electrodes 2302, 2303. Thisrelative proportion between cutting area sizes lead to a relatively highcurrent density (and hence high power density) in tissue close to thecutting electrode, which facilitates localized vaporization, orelectrosurgical cutting of the tissue.

With continued reference to FIG. 58 a, an additional aspect of theillustrated electrode arrangement is that the lower jaw 2301 can be usedfor both coagulation and cutting, regardless of whether the jaws are inan opened or closed position. This multiple functionality isadvantageous when using the tool to spot-coagulate tissue, or to dissecttissue by configuring the tool in a cutting state and brushing the toolagainst the tissue.

Another embodiment of electrode arrangement for a surgical tool isillustrated in FIG. 58 b. In the illustrated embodiment, the upper jaw2306′ is not only used to press tissue against the lower jaw element2301, but it also includes an upper electrode 2307 disposed thereonwhich can be supplied with electrical energy. Tissue can be coagulatedby supplying the two lower coagulation electrodes 2302, 2303 with afirst electrical polarity, and the upper electrode 2307 with a second,opposing polarity from a bipolar electrosurgical unit. Again, it isdesirable that when configured for coagulation, the potential differencebetween the upper electrode 2307 and the two lower electrodes 2302, 2303does not exceed 200V to reduce the risk of arcing to the tissue and thatelectrode 2307 has the same contact area with the tissue as the combinedsurface area of electrodes 2302 and 2303. The latter ensures the sameelectrosurgical effect for both electrode sides.

With continued reference to FIG. 58 b, after hemostasis of the tissuebetween the upper electrode 2306′ and the two lower electrodes 2302,2303 has been substantially achieved, the tissue can beelectrosurgically cut by supplying the electrosurgical cutting electrode2304 with electrical energy. The upper coagulation electrode 2307 on theupper jaw 2306′ can be configured as a return electrode by electricallycoupling it with the corresponding outlet of a bipolar electrosurgicalunit.

With continued reference to FIG. 58 b, when the surgical tool isconfigured as a electrosurgical cutting device, desirably the potentialdifference between the cutting electrode 2304 and the return electrode2307 is between approximately 300-500V. In some embodiments, it can bedesirable that the contact area of the electrodes with the tissue ismuch smaller for the cutting electrode 2304 than with the returnelectrode 2307 on the upper jaw 2306′. For example, in some embodiments,desirably the cutting electrode can have a contact area that is betweenapproximately 1% and 20% as large as a contact area of the returnelectrode 2307. More desirably, the cutting electrode can have a contactarea that is between about 5% and 10% as large as a contact area of thereturn electrode 2307. In one embodiment, the cutting electrode can havea contact area that is approximately 10% as large as a contact area ofthe return electrode 2307. This relative sizing can lead to relativelyhigh current density (and hence high power density) in the tissue closeto the cutting electrode 2304, which facilitates localized vaporization,or electrosurgical cutting of the tissue. With the surgical tool distalend of FIG. 58 b having electrodes 2302, 2303, 2304, 2307 as describedabove, only tissue between the two jaw elements can be coagulated and/orcut. Thus, unlike the embodiment of FIG. 58 a, the tool illustrated inFIG. 58 b is not configured to be used by employing the lower electrodeonly.

Another embodiment of electrode arrangement for a surgical tool isillustrated in FIG. 58 c. In the illustrated embodiment, the upper jaw2306″ includes an upper electrode 2307′, but also shows two cuttingelectrodes 2304 and 2309 that are sandwiched between two coagulationelectrodes 2302 and 2303. In difference to the embodiment shown in FIG.58 b, both coagulation and cutting is distinguished for cases where thehand tool (and hence the jaw members) are fully opened or not fullyopened. With a fully opened tool, tissue can be coagulated by applyingthe two lower coagulation electrodes 2302 and 2303 with opposingpolarities, and will be cut by applying cutting electrode 2304 with thefirst and both electrodes 2302 and 2303 to the second polarity. Indifference, a not fully opened tool will coagulate tissue by applyingboth lower coagulation electrodes 2302 and 2303 with one polarity andelectrode 2307′ to the opposing one, while cutting occurs betweenelectrode 309 and return electrode 2307′. Again, it is desirable thatwhen configured for coagulation, the potential difference between thetwo lower electrodes 2302 and 2303 (tool fully open) or the upperelectrode 2307′ and the two lower electrodes 2302, 2303 (tool not fullyopen) does not exceed 200V to reduce the risk of arcing to the tissue.

The separation of cutting electrodes 2304 and 309 facilitates cutting oftissue that is positioned within the upper and lower jaw elements (notfully opened), or cutting of tissue in contact with the bottom side ofthe tool. The separation prevents inadvertent cutting of tissue.

Another embodiment of electrode arrangement for a surgical tool isillustrated in FIG. 58 d where the upper jaw 2306′″ includes twoseparate electrodes 2307″ and 2308. In this configuration, the upper jawelement 2306′″ can be used to press tissue against the lower jaw element2301, but can also supply electrical energy.

With continued reference to FIG. 58 d, the electrodes 2302, 2303, 2307″,2308 can be selectively configured to a coagulation state. By supplyingthe coagulation electrodes 2302, 2303 on the lower jaw 2301 and the twocoagulation electrodes 2307′, 2308 on the upper jaw 2306′″ withalternating polarities, tissue within the jaws can be coagulated. Forexample, in one possible coagulation state configuration, onecoagulation electrode 2302 on the lower jaw 2301, and one coagulationelectrode 2308 on the upper jaw 2306′″ can be electrically coupled to asource of electrical energy having a first polarity. The othercoagulation electrode 2303 on the lower jaw 2301, and the othercoagulation electrode 2307″ on the upper jaw 2306′″ can be electricallycoupled to a source of electrical energy having a second polaritygenerally opposite the first polarity. While this is an illustrativeexample, it is contemplated that other combinations of connections ofthe electrodes 2302, 2303, 2307″, 2308 with electrical energy sourcesare possible to configure the tool in a coagulation state. It can bedesirable that the contact area of the opposing coagulation electrode(s)are the same to provide the same electrosurgical effect for bothelectrode sides.

With continued reference to FIG. 58 d, after homeostasis of the tissuebetween the upper electrodes 2307″, 2308 and the two lower electrodes2302, 2303 by application of electrical energy with the electrodes inthe coagulation state, the tissue can be electrosurgically cut. Thedistal end of the surgical tool can be configured into a cutting stateby supplying the electrosurgical cutting electrode 2304 with electricalenergy. In various embodiments, one, some, or all of the otherelectrodes 2302, 2303, 2307″, 2308 can be configured to function asreturn electrodes when the tool is in a cutting state by electricallycoupling them with the corresponding outlet of a bipolar electrosurgicalunit.

With continued reference to FIG. 58 d, when the tool is configured in acutting state, the potential difference between the cutting electrodeand the return electrode is desirably between approximately 300-500V.Further, it can be desirable that the relative contact area of theelectrodes with the tissue is much smaller for the cutting electrode2304 than for any of the return electrodes 2302, 2303, 2307″, 2308 orcombinations thereof. For example, in some embodiments, desirably thecutting electrode 2304 can have a contact area that is betweenapproximately 1% and 20% as large as a contact area of one of the returnelectrodes. More desirably, the cutting electrode can have a contactarea that is between about 5% and 10% as large as a contact area of oneof the return electrodes. In one embodiment, the cutting electrode canhave a contact area that is approximately 10% as large as a contact areaof one of the return electrodes. Just as with the embodiment illustratedand described with respect to FIG. 58 a, the electrode arrangementillustrated in the embodiment of FIG. 58 d can be used to spot-coagulatetissue, or to dissect the tissue when “brushing” the tool against it ina cutting mode.

The practicality of the tool configurations of FIGS. 58 a through 58 dcan be further enhanced by selective activation and/or deactivation ofthe selected electrodes. In some embodiments, this selective activationand deactivation can be performed by operator-depressed electricalswitches such as wired or wireless hand or foot operated switches, orswitches positioned on the hand-piece. The electrosurgical unit willthen address specific electrodes, depending on how far the jaws areopened and closed.

FIG. 59 a illustrates a schematic circuit diagram for an electrodearrangement as given in FIG. 58 a. Here, activation of a single-poleelectrical switch 401 connects the outer coagulating electrodes 2302,2303 to opposing polarities, while the center “cutting” electrode 2304remains disengaged. This setting configures the electrodes in acoagulation state. Alternately, activation of a double-pole electricalswitch 402 supplies the center “cutting” electrode 2304 with electricalenergy having a first polarity, and the outer return electrodes 2302,2303 with electrical energy having a second polarity generally opposingthe first polarity. This setting configures the electrodes in a cuttingstate. As a result, the tool can be used for electrosurgical coagulationand/or cutting, and hence can perform the bloodless dissection oftissue.

FIG. 59 b illustrates a schematic power supply circuit that can be usedfor the electrode arrangement shown in FIG. 58 b. In the illustratedembodiment, activation of a double-pole electrical switch 2403 connectsthe two outer coagulating electrodes 2302, 2303 on the lower jaw to asupply of electrical energy of a first polarity, and the coagulatingelectrode 2307 on the upper jaw to a supply of electrical energy of asecond polarity substantially opposite the first polarity. With theswitch 2403 in this position, the cutting electrode 2304 remainsdisengaged. This setting configures the electrodes of the surgical toolin a coagulation state. Alternately, activation of a single-poleelectrical switch 2404 allows the lower jaw electrodes 2302, 2303 to beused for coagulation. The electrode on the upper jaw 2307 and thecutting electrode 2304 remain disengaged in this alternate coagulationconfiguration. To dissect tissue after it has been coagulated, aseparate electrode outlet 2405 on an electrosurgical generator is usedto address the cutting electrode 2304. Desirably, the cutting electrodeis supplied with voltages of 300-500V with respect to the two returnelectrodes 2302, 2303 on the lower jaw.

FIG. 59 c illustrates a schematic power supply circuit that can be usedto address the electrode arrangement of FIG. 58 d. In the illustratedembodiment, activation of a double-pole electrical switch 2406 connectsthe two coagulating electrodes 2302, 2303, 2307″, 2308 on both the lowerand upper jaw to sources of electrical energy having opposingpolarities. The cutting electrode 2304 remains disengaged. This settingcan be used to configure the electrodes of a surgical tool in acoagulation state to coagulate tissue that is clamped between the upperand lower jaw element. Alternately, in other embodiments, a secondcoagulation double-pole switch 2407 can be implemented to separate theactivation of the upper and lower jaws such that one or both jaws can beselectively actuated during a coagulation state. To utilize the lowerjaw of the tool for electrosurgical cutting of coagulated tissue,activation of the cutting double-pole switch 2408 connects the cuttingelectrode 2304 to a source of electrical energy having a first polarityand the two return electrodes 2302, 2303 to a source of electricalenergy having a second polarity substantially opposite the firstpolarity. The voltage supplied by the generator for this setting isdesirably between approximately 300-500V to facilitate electrosurgicalcutting. In the illustrated embodiment, the electrodes 2307″, 2308 onthe upper jaw element remain unaddressed during electrosurgical cutting.

As discussed in more detail above, the activation (or deactivation) ofspecific electrodes can configure the tool in a coagulation state or acutting state. In certain embodiments, the selective activation anddeactivation of specific electrodes can be facilitated by push-buttons,switches, or other electrical switching devices mounted on thehand-piece of the laparoscopic tool, or wired or wireless switches. Inother embodiments, the selective activation and deactivation of specificelectrodes can be facilitated by switches or other electrical switchingdevices that are incorporated into the handle mechanism of thehand-piece to switch at various positions of the jaw elements.

Regarding the circuit shown in FIG. 59 a, referring to the tool shown inFIG. 58 a, switching devices mounted on the hand-piece can be used toallow a user to selectively configure the electrodes on the tool. Switch2401 can be a hand-activated switching device mounted on the hand-piecethat can be selectively activated to configure the electrodes of thetool in a coagulation state. Switch 2402 can be a hand-activatedswitching device mounted on the hand-piece that can be selectivelyactivated to configure the electrodes of the tool in a cutting state. Inanother embodiment, switches 2401, 2402 can be incorporated into thehandle mechanism to such that the tool is automatically switched from acoagulation state to a cutting state at a predetermined position of theclamping members.

One benefit of switching the electrodes from a coagulation state to acutting state at different positions of the jaw elements (e.g., open andnearly closed jaws) can be seen with respect to the embodiment of FIG.59 b. In certain embodiments, switches 2403 and 2404 can be incorporatedwithin the handle of the surgical tool for self-switching based on theposition of the trigger mechanism, rather than on the outside of thehand tool for hand-activation. In one embodiment, switch 2403 can bedisengaged and switch 2404 engaged in a fully open jaw element position.Thus, with the jaw elements fully opened, the switches 2403, 2404 can beconfigured such that only the lower jaw element can be used for spotcoagulation. In this embodiment when the trigger of the hand-piece isactuated to move the jaw elements closed from the fully opened jawposition, switch 2404 is disengaged and 2403 simultaneously engaged.Thus, with the jaw elements moved into a partially-closed configuration,the tool can be used to coagulate or cut tissue that is clamped betweenthe upper and lower jaw element.

In the described embodiment, the electrode switches are automaticallyactuated as the jaw elements are closed. Although the describedembodiment includes a switch point between a coagulation state and acutting state upon commencement of closure from the jaws fully openedposition, other embodiments can have different switching positions. Forexample, with this automatic switching, the switches 2403, 2404 can beconfigured such that the electrodes are activated and deactivated at anyposition in an opening or closing cycle. In other embodiments, asurgical tool can include the electrode configuration of FIG. 58 b andthe switching circuit of FIG. 59 b with the switches 2403, 2404configured for manual actuation, such as by positioning on the toolhand-piece.

Similarly, in certain embodiments, a surgical tool having the electrodeconfiguration of FIG. 58 d with the switching circuit of FIG. 59 c canhave the switches 2406, 2408 incorporated into the trigger mechanism forautomatic switching between a coagulation state and a cutting state atcertain jaw element positions. In certain embodiments, it can also bedesirable to incorporate the second coagulation switch 2407 into thetrigger mechanism of the hand-piece, disengaging the electrodes on theupper jaw element in predetermined jaw position such as a fully openedjaw position. This switching arrangement of the second coagulationswitch 2407 allows for example to spot-coagulate tissue using the lowerjaw element without inadvertently touching tissue with the electrodes onthe upper jaw element. In other embodiments, it can be desirable for thesecond coagulation switch 2407 to be positioned on the hand-piece to bemanually actuated by a user, allowing a user to selectively engage anddisengage the electrodes on the upper jaw element. In other embodiments,all of the switches 2406, 2407, 2408 of the switching circuit of FIG. 59c can be positioned on the hand-piece of the surgical tool to bemanually actuated by the user.

With reference to FIG. 60, one configuration of tool switching isillustrated. In the illustrated embodiment, electrical contacts areincorporated both into the hand-piece 2501 and the trigger 2502. Forexample, as illustrated, the hand-piece 2501 includes a first electricalcontact 2504, a second electrical contact 2506, and a third electricalcontact 507 positioned therein. In the illustrated embodiment, thetrigger 2502 includes a first electrical contact 2503 and a secondelectrical contact 2505. All of the electrical contacts 2503, 2504,2505, 2506, 2507 are positioned to engage and disengage one another atpredetermined relative positions of the trigger 2502 and the hand-piece2501.

With continued reference to FIG. 60, as shown, the first contact 2503 onthe trigger 2502 engages the first contact 2504 on the hand-piece 2501when the jaws are in a fully opened position, but the first contacts2503, 2504 are disconnected when the trigger 2502 is moved from the openposition to close the jaws. In the illustrated embodiment, with the jawsin the fully opened position, the second contact 2505 on the trigger2502 engages the second contact 2506 on the hand-piece 2501. But, thesecond contacts 2505, 2506 are disconnected when the trigger 2502 ismoved from the open position to close the jaws. As the jaws are closedfurther, the second contact 2505 on the trigger 2502 becomes engagedwith the third contact 2507 on the hand-piece 2501, and the firstcontact 2503 on the trigger engages the second contact 2506 on thehand-piece 2501. This engagement allows switching of the polarity of thecontacts 2507 as the hand-piece is closed further. As a result, and withreference to FIG. 58 b, the switching mechanism in FIG. 60 allows foractivation of the upper electrode 2307 and a lower coagulating electrode2303 with opposing polarities in a fully open jaw position. Withprogressive tissue desiccation, the jaws start to close, and the upperelectrode 2307 becomes electrically disengaged (by disconnecting contact2503 and 2504 in FIG. 60), whereas the lower electrode 2303 is switchedto the same polarity as the second electrode 2302 (by connecting contact2505 from 2506 to contact 2507 in FIG. 60). In a separate step, thedesiccated tissue between the upper and lower jaw elements can now beelectrosurgically dissected.

With reference to FIG. 61, another embodiment of a switching mechanismis illustrated with the jaw members in a fully opened position. In theillustrated embodiment, concentric contact strips are disposed on thehand-piece and opposing contact pins are mounted on the trigger. Inother embodiments, contact pins can be mounted on the hand-piece andcontact strips positioned on the trigger. In the illustrated embodiment,trigger movement allows the pin contacts (which are connected tospecific electrodes) to be supplied with electrical energy at certaintool positions. In some embodiments, the polarity of a single pin (i.e.,the same electrode) might change as the jaws are opened or closed.

One contact strip and pin arrangement is illustrated in FIG. 61 for anelectrode configuration of FIG. 3 b. In the illustrated embodiment, pin2601 is electrically coupled to the electrode 2307 (FIG. 58 b) on theupper jaw member and is disengaged. As illustrated, pin 2602 iselectrically coupled to one of the coagulating electrodes 2302, 2303(FIG. 58 b) on the lower jaw. As illustrated, pin 2602 is engaged as thetrigger is moved from the “fully-open” position to a partially closedposition. With further advancement of trigger, pin 2602 changes to thesame polarity as the second coagulating electrode so that both can beused as return electrodes for cutting.

While both FIG. 60 and FIG. 61 show active switching mechanisms in thehand tool (where active electrodes can be switched), which allows thetools to be used with “conventional” electrosurgical generators, FIG. 62shows a configuration for passive switching. Here, a momentary switch2701 is mounted in the handle and is closed by a trigger 2702 when lever2703 is brought into the “fully open” position.

Similarly, FIG. 63 shows the incorporation of two momentary switches2801 and 2802 that are closed by trigger 2803 and 2804 in the “toolfully open” and “tool fully closed” position, respectively. The closingof the momentary switches as shown in FIGS. 62 and 63 is then used forlogic switching of multi-electrode generators, as described in thefollowing.

FIG. 64 shows a schematic of a multi-electrode switching power supplyfor directly connecting individual tool electrodes (such as allindividual electrodes in FIGS. 58 a through 58 d) to an internal RFpower source. Instead of switching two polarities of an externalelectrosurgical unit to different electrodes with active switches in thehand tools, this arrangement facilitates population ofindividually-connected electrodes with different polarities by switchingwithin the power supply. Depending on the tool position, as determinedby tool position switches shown in FIGS. 62 and 63, the electrodes canbe populated differently as determined by pre-determined logic. As such,the five electrode connection points 2901 through 2905 are connected toa relay bank 2906 to a bus bar 2907. Through selected switching of allrelays in the relay bank 2906, each outlet point 2901 through 2905 canbe independently and/or concurrently connected to the plant connectionpoints 2908 and 2909, respectively. The plant connection points 2908 and2909 themselves can be connected through the relay bank 2910 to the twooutlets of a tissue measurement circuit 2911, or a RF plant 2912.

With reference to FIG. 65, in certain embodiments, methods of using anelectrosurgical tool for substantially bloodless tissue dissection areschematically illustrated. The illustrated method includes a positioningstep 2952, a tissue assessment step 2954, anapplying-electrical-energy-to-coagulate step 2956, a tissue measurementstep 2958, a switching step 2960, and anapplying-electrical-energy-to-cut step 2962. In the positioning step2952 an electrosurgical tool having a plurality of electrodes beingconfigurable in one of a coagulation configuration and a cuttingconfiguration is positioned adjacent to tissue to be dissected. Incertain embodiments, the electrosurgical tool comprises aspects of theelectrosurgical tools discussed herein and illustrated in FIGS. 56 and58-63.

In the tissue assessment step 2954, a measurement signal is applied tothe tissue by the coagulation electrodes to determine a future triggerlevel to switch from coagulation to cutting. This determination can beachieved by measuring the product of conductivity and permittivity ofthe tissue, pointing to the desired electrical phase shift switchinglevel for the respective tissue. For example, in some embodiments,desirable cutting switching levels occur at 10 degrees to 40 degrees.More desirably, the preferred switching level for blood vessels isbetween 10 to 30 degrees phase shift, while for highly vascular tissue(such as organs) it is rather between 20 to 40 degrees.

In the applying-electrical-energy-to-coagulate step 2956, electricalenergy is applied to the electrosurgical tool in a coagulationconfiguration to achieve hemostasis in the tissue. In variousembodiments discussed herein, electrode configurations for coagulationare provided. For example, applying electrical energy to theelectrosurgical tool in the coagulation configuration can comprisesupplying one of a plurality of electrodes with electrical energy havinga first polarity and supplying another of the plurality of electrodeswith electrical energy having a second polarity generally opposite thefirst polarity. Desirably, a potential difference between the electrodehaving the first polarity and the electrode having the second polarityis no more than approximately 200 V.

During the coagulation process of the tissue the phase shift betweenapplied voltage and incurred current is measured concurrently in step2958 to provide feedback of the coagulation status. Once thepre-determined switching level is reached, the process will proceed tothe switching step 2960.

In the switching step 2960, as discussed above, some embodiments ofelectrosurgical tool can comprise a handle assembly including aswitching mechanism. This switching mechanism can selectively configurethe electrosurgical tool in either the coagulation configuration or thecutting configuration depending on a position of a trigger of the handleassembly. As discussed above, in some embodiments the switchingmechanism can be configured such that with the electrosurgical tool inan open position, the electrodes are configured in the coagulationconfiguration. The switching mechanism can further be configured suchthat when the electrosurgical tool is moved towards a closed position,the electrodes are configured in the cutting configuration. In otherembodiments, switching of the configuration of electrodes from thecoagulation configuration to the cutting configuration can occur atdifferent predetermined positions of the trigger of the handle assembly.In yet another embodiment, the switching can occur within amulti-electrode power supply as shown in FIG. 64.

In the applying-electrical-energy-to-cut step 2962, electrical energy isapplied to the electrosurgical tool in a cutting configuration todissect the tissue. In various embodiments discussed herein, electrodeconfigurations for cutting are provided. For example, applyingelectrical energy to the electrosurgical tool in the cuttingconfiguration can comprise supplying one of a plurality of electrodeswith electrical energy and configuring another of the plurality ofelectrodes as a return electrode. Desirably, a potential differencebetween the cutting electrode and the return electrode is betweenapproximately 300 V and approximately 500 V.

Electrosurgical Tissue Stapler

Historically, connecting or reconnecting living tissue has involved theuse of suture, clips or staples. More recently, the use of electricityor heat has come to be used to complete the connection of living tissueor seal connected tissue against leakage or bleeding.

However, there remains a need to secure or connect portions of livingtissue, especially conduits, without the use of staples, suture orclips.

An apparatus and method for permanently attaching or connecting livingtissue comprising an electro-surgically generated electrical currentthat is delivered to tissue by a clamping jaw having features thatincrease current density at preferred locations are provided.

Referring to FIGS. 66-72 a surgical tissue fusing or welding instrument3200 having an elongate body 3210, a proximal end 3230 comprising anoperable handle 3235, and a distal end 3220 comprising a jaw assembly isprovided. In some embodiments the jaw assembly can include fixed jaw3280 and an operable jaw 3260 pivotable with respect to the fixed jaw3280. In other embodiments, the jaw assembly can include two operablejaws. As discussed in further detail below, the tissue fusing or weldinginstrument 3200 can be configured to perform a stapling-like procedure,which can desirably be applied, for example in bariatric surgicalprocedures, or other procedures where staple-like closure of tissues isdesirable.

With reference to FIGS. 66-68, in certain embodiments, the elongate body3210 can be sized and configured to be used through a surgical accessport such as a trocar cannula for use in a laparoscopic procedure. Forexample, the elongate body can have an outer diameter corresponding toone of several standard sizes of trocar cannulae, or the elongate bodycan be sized for a non-standard application-specific access port. Inother embodiments, the elongate body 3210 can be sized and configuredfor use in a portless surgical incision.

With continued reference to FIGS. 66-68, the proximal handle 3235 can besized and configured to be usable by one hand of a user. The proximalhandle 3235 can provide connecting features such as an electrical plugfor connection to an electrosurgical surgical generator such as theelectrosurgical generator discussed above with respect to theelectrosurgical system. In some embodiments, the proximal handle 3235can include an operating switch 3240. The operating switch 3240 canallow the user to electrically energize an active portion of the device3200 selectively. The proximal handle can also include a movable lever3236 operatively coupled to the jaw assembly to allow the user to grasp,hold and compress selected tissue between the distal jaw portions 3260,3280. FIG. 66 illustrates the electrosurgical tool 3200 in a closedstate with surfaces 3261, 3281 of the distal jaw portions 3260, 3280proximate one another. FIGS. 67-68 illustrate the electrosurgical tool3200 in an open state with surfaces 3261, 3281 of the distal jawportions 3260, 3280 spaced apart from one another such that tissue canbe received in a gap 3295 formed therebetween.

With reference to FIGS. 69-72, the jaw assembly 3250 of theelectrosurgical tool 3200 can include a plurality of electrodespositioned thereon to simulate stapling action during application. Inthe illustrated embodiment, a plurality of electrodes 3320 is arrangedin pairs in spaced rows within correspondingly spaced recesses 3300 inthe first, fixed jaw 3280. The electrodes extend in four generallyparallel columns extending longitudinally from a proximal end of the jawassembly to a distal end of the jaw assembly. In other embodiments, itis contemplated that the number and arrangement of electrodes can bedifferent from the illustrated embodiment. For example, in someembodiments, the first jaw 3280 can include spaced single electrodes, inother embodiments, the first jaw 3280 can include spaced rows of 3, 4,5, 6, 7, or more than 7 electrodes. In still other embodiments, thefirst jaw 3280 can include geometric arrangements of electrodes such as,for example, electrodes in angled, curvilinear, or shaped rows, orelectrodes can be randomly distributed in corresponding randomlydistributed recesses in the first jaw 3280. For use in bipolar surgicalprocedures, it can be desirable that the electrodes are configured to beapplied in pairs such that one pair member can be electrically coupledto an electrical energy source having a first polarity and the secondmember of each pair can be electrically coupled to an electrical energysource having a second polarity opposite the first polarity. In theillustrated embodiment, the electrodes 3320 are sized and configured toselectively extend and recede into the recesses 3300 to contact tissuepositioned in the jaw assembly as further discussed below.

With continued reference to FIGS. 69-72, In the illustrated embodiment,the second jaw 3260 is pivotably coupled to the first jaw 3280. Asillustrated, the movable second jaw 3260 is hingedly coupled to thefirst jaw 3280 at a proximal pivot point 3290. The second jaw 3260 canbe operatively coupled to the movable lever 3236 such that the jawassembly can be opened and closed by force supplied to the movable lever3236.

With continued reference to FIGS. 69-72, the jaw assembly can furthercomprise a cutting element 3371 such as a slidable or movable cuttingblade. In the illustrated embodiment, the first jaw 3280 comprises alinear slot 3370 that is sized and configured to hold the cuttingelement 3371. In operation, the cutting element is advanceable along theslot 3370 from a proximal position within the first jaw 3280 to a distalposition within the first jaw 3280. In other embodiments, other cuttingelements 3371 can be used in the electrosurgical tool. For example, someembodiments can have reciprocating mechanical cutting blades or radiallyadvanceable cutting elements. Other embodiments of electrosurgical toolcan include electrical cutting elements such as cutting electrodes.

With reference also to FIGS. 73-80 in certain embodiments, theelectrodes 3320 can be urged upward or selectively extended by adistally moving actuation member such as a sled 3380 comprising asubstantially flat elongate body 3381 and at least one cam or peak 3385arranged to contact the electrodes 3320 at desired intervals. In someembodiments, the electrodes 3320 can be arranged in a staggered pattern.In other embodiments, the cams or peaks 3385 on the actuation member maycan be arranged in a staggered pattern to accomplish a sequentialextension of the electrodes 3320. In still other embodiments, all of theplurality of electrodes 3320 can be selectively extended substantiallyconcurrently, such as by movement of a plurality of cams or peaks on anactuation member.

With continued reference to FIGS. 73-80, in some embodiments, theelectrosurgical tool is configured such that a sequential extensionpattern includes a number of electrodes 3320 extended at any givenmoment or with any given force to desirably maximize the force suppliedto the proximal lever 3236 and maximize the current density between theelectrodes 3320 and the compressed tissue 3030. Advantageously,sequential extension and energizing of the electrodes 3320 can preventexcessive thermal damage to compressed tissue 3030 as would be the caseif all electrodes 3320 were to be energized at the same time. Inembodiments of electrosurgical tool including concurrent extension ofthe plurality of electrodes 3320, the electrodes can be sequentiallyenergized to reduce the risk of thermal damage to tissue.

With reference to FIG. 75, in certain embodiments, the electrodes 3320can be electrically coupled to the electrosurgical tool through contactsdisposed on the actuation member or sled 3380. In other embodiments, theelectrodes can be electrically coupled to the electrosurgical toolthrough one or more wires extending longitudinally within the jawassembly, a contact strip disposed on or in one of the jaws, or anotherelectrical coupling. In the illustrated embodiment, electrical contactbetween the actuation member peaks 3385 and electrosurgical tool, whichcan be coupled to an electrical power source such as a generator can beprovided by contact strips 3390, 3391, 3392, 3393 associated with theelongate flat portion 3381 of the movable actuator sled 3380. The sled3380 can be configured to move and energize the electrodes in a sequenceor rhythm. In various embodiments, the sled 3380 can be automatically ormanually controlled.

As discussed further below, in some embodiments, the contact strips3390, 3391, 3392, 3393 can be electrically energized such that theelectrosurgical tool operates as a bipolar surgical tool. In theillustrated embodiment, which includes four longitudinally extendingcolumns of electrodes 3320 (see, e.g., FIG. 71), one of the contactstrips 3390, 3391, 3392, 3393 can electrically couple with one or moreelectrodes 3320 in a corresponding longitudinal column of electrodes. Inother embodiments, other electrical contact arrangements arecontemplated including more or fewer than four contact strips on theactuation member. For example, two contact strips can be relatively wideto each couple with two columns of electrodes in a four electrode columnelectrosurgical tool such as that illustrated in FIG. 71. In otherembodiments, the electrosurgical tool can have more or fewer than fourlongitudinal columns of electrodes and can have a correspondingly moreor fewer than four contact strips.

With reference to FIG. 76, the electrodes 3320 can be configured to beextended and retracted by the sliding actuation member peaks. In theillustrated embodiment, the electrodes 3320 comprise a flat body portion3324 that is sized and configured to nest within recesses 3300 of thefirst jaw portion 3280 and maintain the electrode 3320 in a particularposition depending on the relative position of the actuation member peak3385. The flattened body 3324 can include a contacting surface 323 thatis configured to elevate the electrode 3320 in response to the motion ofan associated cam or contactor peak 3385. The flattened structuralportion 3321 of the electrode 3320 transitions into a pair of pointedpenetrating elements 3325, 3327 that extend through holes in therecesses 3300 of the first jaw 3280.

In operation, as the sled 3380 is advanced distally, the contactingsurfaces 323, 322 of the electrodes 3320 and the cam surfaces 389 of thecontactor peaks 3385 engage and extend the individual pairs ofelectrodes 3320 beyond the contacting face 3281 of the first jaw 3280.As the sled 3380 is advanced distally past a pair of electrodes 3320,the pair retracts into the first jaw 3280. Desirably, the electrodes3320 are configured to be maintained within the jaw assembly afterextension of the electrodes rather than be deposited in tissue once theelectrosurgical tool is removed from a tissue site. As illustrated, theelectrode pairs 3320 do not extend completely out of the first jaw 3280as a contact surface 330 on the upper surface of the flattenedstructural portion 3321 interferes with the contacting face 3281 of thefirst jaw. While the illustrated embodiment illustrates pairedelectrodes 3320 with a connecting flattened structural portion 3321, inother embodiments, single electrodes 3320 can be maintained within thefirst jaw by a flared lower portion or flanged extensions that interferewith the contacting face 3281 of the first jaw.

With reference to FIGS. 77-80, in certain embodiments, the movable lever3236 is configured to actuate both the jaw assembly and moveableelectrodes in a multi-step actuation process. In some embodiments, themovable lever 3236 can be operatively coupled to the jaw assembly suchthat a first action associated with a user grasping the movable proximallever 3236 is that of the jaw assembly grasping selected tissuepositioned therein, such as a body conduit or vessel 3030 (FIG. 77).Upon further movement of the movable lever 3236 by the user, the jawassembly begins to compress the selected, grasped tissue 3030 (FIG. 78)as the movable jaw 3260 continues to pivot from the open state (FIG. 67)towards the closed state (FIG. 66). In the illustrated embodiments, themovable lever 3236 is operatively coupled to the plurality of electrodes3320 in the jaw assembly such that upon advancement of the movable lever3236, the plurality of paired-electrodes 3320 are sequentially advancedby the sled 3380 up from within the first jaw 3280 and toward theopposing face 261 of the movable, second jaw 3260 (FIGS. 79-80).

With reference to FIGS. 79 and 80, as the electrodes 3320 aresequentially advanced through the tissue 3030 compressed between thefirst jaw 3280 and the second jaw 3260, the electrodes 3320 areenergized sequentially as they are extended by electrical coupling tothe contacts 3390, 3391, 3392, 3393 on the sled 3380 (FIG. 75). Thissequential energizing can create an exaggerated current density as theelectrodes 3320 extend into the compressed tissue 3030. Once theelectrodes 3320 have been extended and energized, they are sequentiallydisconnected from electrical contact with the corresponding electricalcontacts on the sled 3380. The disconnected electrodes 3320 can thencool down in contact with the treated tissue 3030. In the illustratedembodiment, only the electrodes 3320 in direct contact with the slidingpeaks 3385 of the actuation sled 3380 are energized. Once the contactorpeaks 3385 have fully extended the electrodes 3320 and moved beyond anyparticular electrode or electrode pair, there is no longer a connectionof the previous electrodes 3320 to a power supply to which theelectrosurgical tool 3200 is coupled. In other embodiments,substantially all of the electrodes 3320 can be energized substantiallyconcurrently by arrangement of electrical coupling to selectivelyprovide energy to the electrodes 3320.

Referring now to FIGS. 81-83, exemplary illustrations of a body conduit3030 that may be closed, occluded, or sealed and subsequently separatedare shown in accordance with certain embodiments of a jaw assembly of anelectrosurgical tool 3200. In FIG. 81, the conduit 3030 is firstselected and grasped. In FIGS. 82-83, the grasped tissue 3030 is fullycompressed between distal jaws 3260, 3280. The movable lever 3236associated with the proximal handle 3235 can be further actuated and theelectrodes 3320 are sequentially energized and elevated into thecompressed tissue 3030 (see, e.g., FIGS. 77-80). When the tissue 3030 isfully fused or welded in response to the energy supplied by theelectrodes, a cutting element 3371 may be selectively advanced, asfurther discussed below with respect to FIGS. 98-100. The cuttingelement 3371 is sized and configured to cut the conduit or tissue 3030between rows of electrode fusion leaving a plurality of fusion rows oneach side of the cut. The electrodes 3320 are subsequently withdrawnfrom the selected tissue 3030 as the jaws 3260, 3280 are separated (see,e.g., FIGS. 77-80).

With reference to FIGS. 84-85, certain aspects of a bipolarelectrosurgical tissue fusion operation are illustrated. In previousbipolar surgical tools, electrical energy of a first polarity (+) can beprovided to surface contact electrode pins 3405 on a first paddle 3400,and electrical energy of a second polarity (−) can be provided toelectrode pins 3425 on a second paddle 3420. The paddles can becompressed over tissue such as a vessel having two portions 3030, 3030′such that the first paddle 3400 compresses an outer wall 3036 of thefirst portion 3030, and the second paddle 3420 compresses an outer wall3037 of the second portion 3030′. In order for the two portions oftissue to be welded or fused together, the electrical energy must travela relatively long distance between the pins 3405, 3425 to the interfacebetween inner walls 3033, 3034 of the tissue portions 3030, 3030′. Asthe distance between pins increases in a bipolar electrosurgicalinstrument, the current density tends to decrease. Therefore, using sucha device, it can be necessary to apply electrical energy over a fairlylong duration, which can undesirably damage tissue 3030, 3030′.

With reference to FIGS. 86-91, advantageously, with an electrosurgicaltool 3200, high current density of a short duration can produceeffective seals/welds and with minimal or substantially no radiantthermal effects. Unlike conventional surface contact electrodes, anexemplary inserted electrode 3325 in the electrosurgical tool 3200 canprovide a dense current path resulting in elevated thermal activitywithin the compressed tissue 3030. The margin of thermal damageconcomitant to electrosurgical surface radiation is potentiallynoteworthy and as such the minimization or elimination of the margin ofradiant thermal damage by inserting the electrodes 3325 such as, forexample with sharpened or tapered tips 3326 to allow the electrodes 3325to penetrate tissue to be fused. In other embodiments, the electrode3325 can be otherwise configured to direct the current path in a mannerthat concentrates or focuses the energy at a particular location.

A section view of the activity associated with the electrodes 3325 maybe seen in FIGS. 86-91 where a penetrating electrode element 3325 isinserted through or into a portion of compressed tissue 3030 throughaction of the tapered tip 3326 to create an interface surface 3470within the tissue 3030. Energy from an energy source is supplied to theelectrode 3325 and subsequently radiated into the adjacent tissueradially from the interface surface 3470. As the tissue is energized, itheats to a particular temperature at which it loses fluid content. Thetissue 3030 then fuses at the cellular level in a manner that resemblescross-linking. The cross-linked collagen forms a continuous structure3465 of denatured cells. When the electrode 3325 is removed, thedenatured structure 3465 remains. As illustrated in FIGS. 89-91, thedenatured structure 3465 may serve as a connecting structure 3475between two portions of tissue 3030, 3030′ such as two opposing walls3033, 3034 of a compressed conduit 3030 that have been compressed toform a closure or occlusion. When fused with an electrosurgical tool3200 described herein, the denatured structure 3475 generally extendsthrough all tissue that has been compressed between the jaws 3260, 3280of the electrosurgical tool 3200 and energized by the movable electrodes3320. The denatured structure 3475 can resemble an “hourglass” shapewhere there is a wide first, insertion portion, a narrow mid portion anda wide exit portion.

Electro-surgery involves managing the timing and temperature of theprocedure. Too little generated heat within the tissue prevents thetissue from properly fusing or welding and too much heat within thetissue may destroy it and result in complications. As such, theelectrosurgical tool can be less sensitive to the variables withinliving tissue. The instrument may be coupled to feedback systems thatmeasure or respond to conditions that develop within treated tissue. Forinstance, the electrosurgical tool may desiccate tissue during theheating phase so that resistance to electrical current develops. In someembodiments, that resistance may be measured or otherwise used tocontrol the delivery of electrosurgical energy to the electrodes. Insome embodiments, the phase changes between the initiation of theelectrosurgical energy and any subsequent point during the delivery ofthe electrosurgical energy may be used to control the delivery. In otherembodiments, a measurement of the temperature of the treated tissue canalso be used to control the delivery.

A comparison between various methods of conduit occlusion may beappreciated in FIGS. 92-95. FIG. 92 illustrates a sutured conduit 3030.The sutured conduit 3030 comprises a plurality of individual or runningsutures 3480 terminating in at least one knot 3481. The suturing processcan require expertise, be time consuming, and may not always result inoptimum occlusion. As a result the conduit 3030 may leak or ooze.

FIG. 93 illustrates a stapled conduit 3030 in which a plurality ofstaples 3490 have been driven into the conduit 3030. The staples 3490have folds 3491 to retain them in the conduit 3030 and apply occlusiveforces to the conduit. Stapling using a surgical stapler, results in amore secure closure than suturing in many cases. However, even withstapling, suturing may be used to complete the closure since staples3490 may not accommodate the wide variations in tissue thickness ortexture. Several surgical procedures make use of stapling. In thesecases, most of the staples 3490 remain within the surgical site.Generally, the staples 3490 are made from metal, such as titanium. Itmay be appreciated that a great deal of force is applied to the jawportions of a stapling device to accomplish all the actions required toocclude the subject tissue 3030 and subsequently insert the staples 3490and fold 3491 them appropriately. It should also be noted that thecartridges holding the staples 3490 are complex and expensive devicesand hold only a single load of staples 3490. Therefore, there aregenerally several exchanges of stapling instruments during a typicalsurgical procedure. For example, during a surgical procedure involvingthe intestines, it is not uncommon to use, between three and tencartridges of staples with each cartridge holding, up to thirty-six ormore staples. The residual metal mass left behind is thereforesignificant. Moreover, if removal is desired, staples are not easily cutand, in addition, some of them may be dislodged during a cuttingprocedure. This may result in residual pieces of metal within a bodycavity. In addition, electro-cautery is often used to completely seal avessel or conduit 3030 that has been stapled.

With reference to FIG. 94, compressive, external electrosurgical fusionsuch as applied by surface contact electrodes described above withrespect to FIGS. 84 and 85 can be adequate for small vessels orconduits. However, as discussed above, there may be excessive radiantthermal damage associated with the use of these modalities, especiallyin larger conduits 3030. Thermal damage that eliminates the regenerationof residual tissue or prevents vascular re-perfusion or regeneration isundesirable in most cases. Accordingly, compressive, externalelectrosurgical fusion can be undesirable in relatively larger vesselsor conduits where thermal damage can occur. Additionally, in someinstances, compressive electrosurgical fusion can fail to providesufficient compressive forces, resulting in non-occluded areas 3032adjacent the conduit wall 3031. Both suturing and stapling accommodateregeneration when done properly in most cases. However, surgicalstapling can often be responsible for necrosis of residual tissue sincethe delivery devices do not compensate well for variations in tissuethickness or texture.

As is apparent from the above discussion and FIG. 94, theelectrosurgical tool 3200 described herein can fuse or weld in a mannerthat emulates the placement of a plurality of staples. The portions oftissue that have been treated resemble a connection made by staples.Moreover, with the electrosurgical tool 3200 described herein, unlike astapler, the second, closing jaw does not have to be of sufficientstrength to provide an anvil for the folding or bending of staple legs.Thus, the electrosurgical tool 3200 can be particularly advantageous inapplications where the device may have to be operated through a smalltubular access port.

With reference to FIG. 95, compressing selected tissue and subsequentlycreating a plurality of denatured connecting structures 3475 for examplewith an electrosurgical tool 3200 as described herein provides acombination of occlusive security and minimal thermal radiation damage.Adequate vascular regeneration and minimization of necrosis of residualtissue are also provided. Accordingly, use of the electrosurgical tools3200 described herein for conduit occlusion can desirably provideadvantages of tissue suturing or stapling with reduction of thedrawbacks of external contact electrosurgical fusion. Advantageously,sealing a conduit with an electrosurgical tool 3200 as described hereincan also be accomplished relatively quickly and easily by a surgeon.

With reference to FIG. 96, experimental data for sealing strength ofvarious embodiments of electrosurgical tools is presented graphically.Various experiments were performed on porcine small intestinal tissue todemonstrate the strength of sealing of an electrosurgical tool 3200 asdescribed herein. Using tools having trenchwidth (that is, spacingbetween adjacent electrodes) of between 0 and 0.055 inches, porcineintestinal tissue was sealed using the electrosurgical tool 3200described herein and its burst pressure measured. As a control, it wasinitially established that a conventionally stapled section ofintestinal tissue can withstand a burst pressure of 0.5+−0.1 pounds persquare inch. Multiple tests were conducted at various trenchwidths, anda statistical range of the results was plotted in FIG. 96, with meandata for each trenchwidth appearing at a point designated in the range.As is apparent from FIG. 96, for relatively small trenchwidths, theelectrosurgical tool 3200 can create an intenstinal tissue seal burststrength that outperforms conventional stapling. For relatively largetrenchwidths, the electrosurgical tool 3200 can create an intenstinaltissue seal burst strength that performs similarly to, or marginallyless than conventional stapling. Accordingly, the electrosurgical tools3200 described herein offer similar or increased burst strengthperformance while being faster and easier to use and having otheradvantages discussed above.

Referring to FIGS. 97-100, as discussed above, in some embodiments, thejaw assembly of the electrosurgical tool 3200 can include a cuttingelement 3371 such as a selectively operable cutting component. Thecutting component can be selectively moved between a proximal locationand a distal location to cut tissue compressed between the jaws of thejaw assembly. In various embodiments, the cutting element 3371 can be asharp blade, hook, knife, or other cutting element that is sized andconfigured to cut between denatured structures 3475 in compressedtissue. As illustrated in FIG. 99, in some embodiments, the cuttingelement 3371 includes a sharpened edge 3372 on one of the proximal edgeor the distal edge to allow cutting of tissue when the cutting element3371 is moved in one direction towards the sharpened edge 3372. Asillustrated in FIG. 100, in some embodiments, the cutting element 3371includes a first sharpened edge 3372 and a second sharpened edge 373 oneach of the proximal edge and the distal edge of the cutting element3371 to allow cutting of tissue when the cutting element 3371 is movedeither proximally or distally along the slot 3370 in the fixed jaw 3280.

While in illustrated embodiments, the cutting element is illustrated asa mechanical element, in other embodiments, the cutting element 3371 cancomprise an energizable element or wire that can be selectivelyenergized by a generator or power source. An electrosurgical cuttingelement 3371 can easily separate the compressed and fused tissue portionand can additionally provide fluid stasis or additional sealing of thelumen 3032 associated with the treated tissue 3030.

FIGS. 101-106 illustrate various configurations of current intensifyingelements 3500, 3510, 3520, 3522, 3524, 3526, 3530, 3540, 3545, 3550 foruse in an electrosurgical tool such as the electrosurgical tool 3200described herein. The elements can be configured to focus or directenergy on or into a position within compressed tissue 3030. Thus, invarious embodiments an electrosurgical tool can include a plurality ofcurrent intensifying elements in place of or in addition to a pluralityof extendable electrodes as discussed above. Each of the various currentintensifying elements can be desirable for certain surgical environmentsdepending, among other considerations, on the depth of tissuepenetration desired and the degree of energy intensification desired. Insome embodiments, an electrosurgical tool can include a plurality ofextendable electrodes as described above on one jaw of a jaw assemblyand a plurality of current intensifying elements on the other jaw of thejaw assembly. In other embodiments, an electrosurgical tool can includea first plurality of current intensifying elements on one jaw of the jawassembly and a second plurality of current intensifying elements on theother jaw of the jaw assembly.

In some embodiments, the elements can comprise holes 3500 that functionas energy horns, as shown in FIG. 101. In other embodiments, theelements can additionally comprise rods 3510 or spikes that arestationary or movable, as depicted in FIG. 102. As an alternative, someapplications may use a less intrusive configuration such as a pluralityof subtle arcs or mounds 3520 (FIG. 103 a). Some applications may favora slightly more aggressive configuration comprising a plurality ofraised squares 3522 (FIG. 103 b), rods 3524 (FIG. 103 c),“ball-and-cup”-like configurations 3526 (FIG. 103 d), or rectangles 3530(FIG. 104) where energy can be focused or concentrated at edges andcorners. In other embodiments, the elements can comprise a plurality ofelongate rows 3540 (FIG. 105 a) or socket-and-spickets 3545 (FIG. 105b). In other embodiments, the elements can comprise a plurality ofpyramids or cones 3550 (FIG. 106) or the like that are sized andconfigured to penetrate into the surface of tissue.

FIG. 107 illustrates a cross-sectional view of tissue that has beencompressed and fused with an electrosurgical tool. As illustrated, thetissue 3030 is compressed within a square-patterned embodiment of theupper 3260 and lower jaw 3280 elements, and subjected to electrical RFcurrent or thermal energy. This energy application can be accomplishedby connecting both upper and lower jaw elements to a bipolarelectrosurgical unit, or by encapsulating electrical (ohmic) heaterswithin each jaw element. Even though there can be some compressionbetween “uncompressed” tissue areas, as well as some energy overspillinto the “uncompressed” tissue area, the directly compressed andenergized tissue areas will be the first areas to fuse together and canbe the only ones to seal.

With reference to FIG. 108 a, an example of the visual appearance of theobtained results on a fused and separated blood vessel 3030 isillustrated. As can be seen, each of the two sections of a sealed andcut vessel may include a pattern corresponding to the pattern ofelectrodes or current intensifying elements. For example, as shown inFIGS. 103 a-b, the divided portions of the vessel are each sealed in afluid tight manner by the respective double-rows of fused squares. Thetissue between the fused squares, on the other hand, does not have to befused, or even connected. For example, with reference to FIG. 108 b, across-section along line 8-8 in FIG. 108 a illustrates the fused andnon-fused areas in the cut vessel. In this example, the fused anddenatured (square) tissue elements are separated by tissue areas thathave not been connected to opposing tissue areas.

FIG. 109 a illustrates an exemplary sealed and cut tissue segment 3030,obtained by welding the tissue in two double-rows of round areas, andcutting the tissue between the two double rows. The divided portions ofthe tissue are each sealed in a fluid tight manner by the respectivedouble-rows of fused circles. The tissue between the fused circles, onthe other hand, does not have to be fused, or even connected. This isshown, for example, in FIG. 109 b, which depicts a cross-section alongline 9-9 in FIG. 109 a. In this example, the fused and denatured(circular) tissue elements are separated by tissue areas that have notbeen connected (to opposing tissue areas).

With reference to FIG. 110, tissue 3030 within a jaw assembly 3250 of anelectrosurgical tool having square patterned recesses is illustrated incross-section. As illustrated, the tissue 3030 is compressed within thesquare pattern of the upper and lower jaw elements. In some embodimentsof electrosurgical tool, energy can be supplied to the tissue byapplying the upper electrode with ultrasonic energy, which can causefriction of the tissue with both upper and lower jaw element. Themovement of the upper jaw element in FIG. 110 is indicated forillustrative purposes as parallel to the drawing plane, although themovement can also be provided in the transversal direction. Even thoughthere will be some compression between “uncompressed” tissue areas intothe “uncompressed” tissue area, also through heat conduction by thetissue, the directly compressed and energized tissue areas can beinitially fused and can be the only areas to seal.

Referring to FIG. 111, tissue 3030 within a jaw assembly 3250 of anelectrosurgical tool having square patterned recesses is illustrated incross-section. Energy is then supplied to the tissue by irradiating itwith UV and/or IR radiation, provided for example through fiber-opticalcables within the square-patterned areas. Even though there will be somecompression between “uncompressed” tissue areas, as well as some UV/IRenergy overspill into the “uncompressed” tissue area, also throughscattering, the directly compressed and energized tissue areas will bethe first ones and can be the only ones to seal.

It is believed that UV (200 to 400 nanometers) is absorbed by proteins(and hemoglobin), leading to cleavage of chemical bonds within theproteins, while IR (>1 micrometer) is strongly absorbed by water,causing heating of the tissue. It has been demonstrated that the fusionof clamped arteries using incoherent UV within the spectral range of 300to 500 nanometers, without substantial heating of the artery can beaccomplished. The irradiation of the pressurized tissue with UV cancause collagens to bind each other through photochemical reactions,without desiccation or thermally-induced collagen degeneration.

In one aspect, the tissue is fused or welded in a manner that emulatesthe placement of a plurality of staples. The portions of tissue thathave been treated resemble a connection made by staples. However, usingthe electrosurgical tool, a single grasping procedure can simulate therelease of tens of staples, thus resulting in significant time savingsover a similar procedure with a surgical stapler. When compared with asurgical stapler, advantageously, the second, closing jaw of theelectrosurgical tool does not need to be of sufficient strength toprovide an anvil for the folding or bending of staple legs. It maytherefore favor laparoscopic applications where the device may have tobe operated through a small tubular access port.

Although this application discloses certain preferred embodiments andexamples, it will be understood by those skilled in the art that thepresent inventions extend beyond the specifically disclosed embodimentsto other alternative embodiments and/or uses of the invention andobvious modifications and equivalents thereof. Further, the variousfeatures of these inventions can be used alone, or in combination withother features of these inventions other than as expressly describedabove. Thus, it is intended that the scope of the present inventionsherein disclosed should not be limited by the particular disclosedembodiments described above, but should be determined only by a fairreading of the following claims.

1. A method for controlling an output of an electrosurgical generatoroperatively coupled to a bipolar electrosurgical device, comprising:measuring a phase angle of a first measurement signal applied to tissueof a patient via at least one electrode of the electrosurgical device,the first measurement signal applied to the tissue prior to treatment ofthe tissue by the electrosurgical device; determining a target phaseangle using the phase angle of the first measurement signal; followingdelivery of a treatment signal to the tissue, measuring the phase angleof a second measurement signal applied to the tissue, the treatmentsignal capable of causing modification of the tissue; and ceasingdelivery of the treatment signal to the tissue when the phase angle ofthe second measurement signal reaches the target phase angle.
 2. Themethod of claim 1, wherein the treatment signal and the secondmeasurement signal are alternatively applied to the tissue in a timeinterleaved fashion.
 3. The method of claim 1, wherein the treatmentsignal and the second measurement signal are applied to the tissuesubstantially simultaneously.
 4. The method of claim 1, whereinmodification of the tissue comprises tissue fusion.
 5. The method ofclaim 1, wherein modification of the tissue comprises coagulation.
 6. Amethod for controlling an output of an electrosurgical generatoroperatively coupled to a bipolar electrosurgical device, comprising:determining permittivity and conductivity of tissue of a patient using ameasurement signal, the measurement signal applied to tissue of apatient via at least one electrode of the electrosurgical device, themeasurement signal applied to the tissue prior to modification of thetissue by the electrosurgical device; determining a threshold phaseangle based on the permittivity and the conductivity of the tissue;measuring a phase angle of a signal applied to the tissue; and ceasingthe delivery of the treatment signal to the tissue when the phase angleof the signal reaches the threshold phase angle.
 7. A method ofcharacterizing tissue prior to the delivery of electrosurgical energy tothe tissue via a bipolar electrosurgical device, comprising: measuringphase angle of a measurement signal applied to tissue of a patient viaat least one electrode of the electrosurgical device, the measurementsignal applied to the tissue at a predetermined frequency prior tomodification of the tissue by the electrosurgical device; determiningthe product of the relative permittivity and conductivity of the tissueusing the phase angle measurement and the predetermined frequency;characterizing the tissue based on the product of the relativepermittivity and conductivity of the tissue.
 8. The method of claim 7,further comprising controlling the delivery of a treatment signal to thetissue based at least in part on the characterization, the treatmentsignal capable of causing modification of the tissue.
 9. The method ofclaim 7, wherein the characterizing comprises determining a treatmentendpoint.
 10. The method of claim 7, wherein the characterizingcomprises determining a tissue type.
 11. A method of characterizingtissue prior to the delivery of electrosurgical energy to the tissue viaa bipolar electrosurgical device, comprising: generating a measurementsignal applied to tissue of a patient positioned between at least twojaw members of an electrosurgical device, at least one of the jawmembers comprising an electrode, the measurement signal delivered to thetissue via the electrode and applied to modification of the tissue bythe electrosurgical device; determining a treatment endpoint conditionusing the measurement signal, the treatment endpoint conditiondetermined substantially independent of the dimensions of the tissuepositioned between the at least two jaw members; and stopping deliveryof a treatment signal to the tissue when the treatment endpointcondition is reached, the treatment signal capable of causingmodification of the tissue.